APPARATUS AND METHOD FOR THE SIMULTANEOUS TREATMENT OF DIFFERENT FLUCTUATING GAS FLOWS

Description

[0001] The present invention relates to a new apparatus and a method for the simultaneous separation of several gas streams with different compositions by means of gas separation membranes, wherein the gas streams supplied to the apparatus or the method may be subject to fluctuations in their respective volume flows and compositions.

[0002] Simultaneous separation of multiple gas streams with different and fluctuating compositions may be necessary, for example, in the ex-situ methanization of biogas or similar gases with hydrogen, when the hydrogen stream is only available in fluctuating quantities, as is often the case with hydrogen from electrolysis plants powered by electricity from renewable sources such as wind power. WO2015 / 0I7875 describes a process in which biogas and the methanization product gas are separated simultaneously or alternately. The problem of fluctuating reactant and product streams is solved using complex gas or liquid storage systems.

[0003] Alternative approaches for treating different, fluctuating gas flows with gas separation membranes include processes in which either separate separation units are provided for the various gas flows or in which the flows are mixed and fed to the separation unit as a single mixed flow. With these methods, the desired separation result cannot be achieved, or only with significantly more effort. Furthermore, fluctuations in the gas flows with regard to quantity or composition must be compensated for, potentially requiring substantial adjustments to operating parameters such as pressure, temperature, and membrane area. Providing corresponding excess capacity or gas storage is expensive.

[0004] For example, US patent 2020 / 0254383 discloses a system for separating gas mixtures that has only one feed gas line. This system is not capable of efficiently handling two different, fluctuating gas flows with different compositions and volume flows without complex control technology.

[0005] Therefore, there is a high demand for efficient equipment and methods for the simultaneous separation of multiple gas streams with different compositions.

[0006] The object of the present invention was therefore to provide a new apparatus and a new method which do not have the disadvantages of the prior art apparatus and methods, or only to a reduced extent.

[0007] A particular objective of the present invention was to provide a new apparatus and a new method with which the treatment of different, fluctuating gas flows can be achieved as simply as possible, preferably with the lowest possible excess capacity with respect to membrane area and / or gas storage and / or compressor power and / or temperature control and / or pressure control.

[0008] Another specific objective of the present invention was to provide a new apparatus and a new method which do not require complex control technology.

[0009] Another specific objective of the present invention was to provide a new apparatus and a new method which have a very high degree of flexibility with regard to the use of the gas streams obtained after separation.

[0010] Another specific objective of the present invention was to provide a new apparatus and a new method suitable for the use of renewable energies, which are only available in highly fluctuating quantities, and thereby to contribute to climate protection.

[0011] Another specific objective of the present invention was to provide a new apparatus and a new method which makes it possible to bring potentially strongly opposing fluctuating gas flows to the desired target purities of the respective product streams for virtually any operating point using the simplest possible apparatus.

[0012] Further tasks not explicitly mentioned arise from the overall context of the following description, examples, claims and illustrations.

[0013] The inventors have now surprisingly discovered that the aforementioned problems can be solved with an apparatus according to claim 1 and a method according to claim 16. Preferred embodiments are claimed in the dependent claims.

[0014] The apparatus and method according to the invention are characterized in that two or more feed gas streams, which differ in their composition, are fed to a membrane separation stage, wherein the membrane separation stage contains one or more membrane blocks, the membrane block or membrane blocks each comprise several membrane separation units connected in parallel, the feed gas streams are fed to a gas distribution system at spatially separated locations such that two or, preferably, more than two membrane separation units are arranged between the connection points of the feed gas streams.

[0015] To illustrate this further, using a membrane block to which two feed gas streams 1 and 2 are supplied, this means that, through the gas distribution system according to the invention, feed gas stream 1 with composition 1 is supplied to one or more membrane separation units of the membrane block, and feed gas stream 2 with composition 2 is supplied to one or more membrane separation units of the membrane block that differ from the above-mentioned membrane separation units. Furthermore, mixed gas streams containing, preferably, a mixture of feed gas streams 1 and 2 can also be supplied to other membrane separation units of the membrane block, through the gas distribution system according to the invention. Preferably, as few as possible, and particularly preferably none, of the membrane separation units of the membrane block are supplied with mixed gas streams, and as many membrane separation units of the membrane block as possible are supplied with either feed gas stream 1 or feed gas stream 2.

[0016] The gas distribution system according to the invention allows the number of membrane separation units to which the respective different gas flows are supplied to be adjusted or actively controlled / regulated. Preferably, the adjustment is made by the volumetric flow rate or mass flow rate of the respective feed gas flows and / or by the inlet pressure of the feed gas flows relative to each other. This means, for example, that if the volumetric flow rate and / or the mass flow rate and / or the pressure of a feed gas flow decreases, fewer membrane separation units are supplied to this feed gas flow in the respective membrane blocks, while at the same time another feed gas flow is supplied to more membrane separation units.If control is achieved via the pressures of the feed gas flows, the applicable differential pressure range between the feed gas flows according to the invention is limited by the fact that the respective differential pressures of the feed gas flows result in each feed gas flow being supplied to at least one membrane separation unit of the membrane block. If the differential pressure becomes too high, the feed gas flow with the lower pressure could be completely displaced from the membrane separation stage.

[0017] The apparatus and method according to the invention have the advantage that, in the event of opposing capacity requirements of the feed gas streams to be separated, a flexible and rapid response is possible, and the separation capacities in the separation stages and membrane blocks can always be optimally utilized. A particularly significant advantage of the apparatus and method according to the invention is that control and regulation can be achieved without extensive technical and control engineering effort, such as a large number of automatic valves, and that more of one feed gas stream can be processed than another.

[0018] The gas distribution system according to the invention also has the advantage that it can be designed such that the gas streams to be purified can be fed to the respective membrane separation units without or with only minimal mixing. This allows the various membrane separation units to be supplied with feed gas streams to be separated in their original or largely original composition. Such a system, in turn, has the advantage that different feed gas streams within an installation can be treated largely separately.

[0019] By allowing different gas streams in their original or largely original composition to be supplied to the individual membrane separation units, different permeate and retentate streams are obtained in the different membrane separation units in terms of composition and / or volume flow.

[0020] The apparatus and method according to the invention require no complex additional equipment, or significantly fewer or smaller additional devices, such as buffer tanks and / or pressure accumulators for compensating for fluctuations in the different gas flows to be purified. They therefore offer considerable economic advantages. The apparatus and method according to the invention are particularly characterized by the fact that these fluctuations can be compensated for with minimal equipment, so that constant product flows can be obtained in terms of their volumetric flow rate and / or composition.

[0021] If, for example, the pressure of the first feed gas stream drops within the permissible range for the differential pressure to the second feed gas stream according to the invention, this merely results in fewer membrane separation units being supplied to this feed gas stream and more membrane separation units being supplied to the second feed gas stream in the inventive device or method according to the invention. No membrane separation unit has to be operated under partial load; the permeate and retentate pressures can be kept constant.

[0022] If, on the other hand, an apparatus such as the one shown in the comparative example were used, i.e., the first feed gas stream is fed to a first membrane separation stage and the second feed gas stream to a second membrane separation stage, and the pressure in the first feed gas stream were to decrease, this would result in a simultaneous decrease in the pressure of the retentate gas streams of the first membrane separation stage, and a second compressor would have to be used to recompress these retentate gas streams.

[0023] If the volume of the first feed gas stream decreases, in the device or method according to the invention, this simply results in fewer membrane separation units being supplied to this feed gas stream and simultaneously more membrane separation units being supplied to the second feed gas stream. No membrane separation unit needs to be operated under partial load, and the permeate and retentate pressures can be kept constant. If, however, an apparatus like the one shown in the comparative example were used, i.e., supplying the first feed gas stream to a first membrane separation stage and the second feed gas stream to a second membrane separation stage, and the volume in the first feed gas stream were to decrease, the separation capacity of the first membrane separation stage would have to be adjusted. Possible measures would be switching off membrane separation units by means of valves, adjusting the operating temperature, increasing the permeate pressure, or reducing the retentate pressure.A reduction in the retentate pressure could still be implemented with relatively little effort; however, a drop in the pressure of the retentate gas streams would often necessitate a second compressor or booster to recompress the retentate gas streams, since a constant pressure of the retentate gas streams is often required for further use of the retentate.

[0024] The apparatus and method according to the invention are particularly advantageous for increasing the use of renewable energies, since these are often only available in highly fluctuating quantities. They thus make an important contribution to climate protection.

[0025] Further advantages not explicitly mentioned arise from the overall context of the following description, examples, claims and illustrations.

[0026] Individual features that are subsequently specified and / or illustrated in connection with specific embodiments are not limited to these embodiments or their combination with the other features of these embodiments, but can be combined within the scope of technical possibilities with any other variants, even if they are not specifically addressed in the present documents, provided they fall within the scope of protection of the claims.

[0027] Identical reference numerals in the individual figures and illustrations of the drawings denote identical or similar components, or components with the same or similar effects. The representations in the drawing also clearly indicate features that are not marked with reference numerals, regardless of whether such features are described subsequently or not. Conversely, features included in this description but not visible or depicted in the drawing are readily understandable to a person skilled in the art.

[0028] The present invention relates to a system for separating gas mixtures, comprising a. a first feed gas line (7) suitable or configured to transport a first feed gas stream, and a second feed gas line (8) suitable or configured to transport a second feed gas stream, the composition of which differs from the first feed gas stream; b. a membrane separation stage comprising a membrane block (1) or several membrane blocks (1), wherein the membrane block (1) / membrane blocks (1) each comprise several parallel-connected membrane separation units (2), wherein ∘ each membrane separation unit (2) has a gas inlet (3) and gas separation membranes and separates the gas mixture supplied through the gas inlet (3) into a retentate gas stream and a permeate gas stream by means of the gas separation membranes, and ∘ each membrane separation unit (2) has a retentate gas outlet (30) for the retentate gas stream.which is preferably connected to a retentate gas line (9) or is connected by means of one or more retentate connecting lines (32) to one or two retentate gas outlets (30) of the adjacent membrane separation unit(s) (2) of the same membrane block (1), and has a permeate gas outlet (31) for the permeate gas stream, which is preferably connected to a permeate gas line (10) or is connected by means of one or more permeate connecting lines (33) to one or two permeate gas outlets (31) of the adjacent membrane separation unit(s) (2) of the same membrane block (1), and c. a gas distribution system configured to include connecting lines (18) that each connect the gas inlets (3) of two adjacent membrane separation units (2) of a membrane block (1), preferably directly and immediately, and / or one or more distribution lines (4) that each contain several branches (5),the membrane separation stage comprises, each connected by means of separate supply lines (6) to the gas inlets (3) of the individual membrane separation units (2) of a membrane block (1), wherein one or more branch(es) (5) may additionally also have a connection option for a feed gas line, so that by means of the branch(es) (5) a feed gas line and a supply line (6) may be connected simultaneously to the respective distribution line (4), and, if the membrane separation stage comprises several membrane blocks (1), pipes, preferably pipes (19a, 19b, 20a, 20b) that connect the membrane blocks (1) of the membrane separation stage to each other, the first feed gas line (7), the second feed gas line (8), and optionally further feed gas lines, independently of each other, at spatially separated locations, each to a distribution line (4) or a connecting line (18) or a branch (5), or, if present,to a pipeline connecting the membrane blocks (1) of the membrane separation stage, preferably a pipeline (19a, 19b, 20a or 20b), or to a gas inlet (3) of a membrane separation unit (2), preferably directly, wherein the connection points are arranged such that two or more than two branches (5) and / or two or more than two gas inlets (3) are arranged between the connection points of the first feed gas line (7) and the second feed gas line (8).

[0029] The number of branches (5) and / or gas inlets (3) between the connection points of the first feed gas line (7) and the second feed gas line (8) is preferably at least 3, particularly preferably at least 4, very preferably at least 5, especially preferably at least 7, and very preferably at least 9. The upper limit can, for example, correspond to the number of membrane separation units per block, but can also be increased further in the case of multiple membrane blocks per membrane separation stage, as, for example, in Figure 4a and 5a shown.

[0030] If more than two feed gas lines are supplied to a membrane separation stage according to the invention, the connection points of the feed gas lines are preferably arranged spatially such that two or more than two branches (5) and / or two or more than two gas inlets (3) are arranged between the connection points of each pair of feed gas lines. Examples of this can be found in Figures 4 to 9.

[0031] Under a "Line" Within the scope of the present invention, pipelines are understood to be those through which gas flows.

[0032] Under "a pipeline that is directly and immediately connected to another pipeline", Within the scope of the present invention, it is understood that a gas stream, at the moment it exits the first of the two immediately and directly connected pipelines, enters the second of the immediately and directly connected pipelines, i.e., no third pipeline, must pass between the first and second pipelines.

[0033] One Membrane separation unitThe membrane separation unit is essentially characterized by the presence of technically usable connections for the pressure-side supply of a gas stream to be separated (gas inlet (3)), the so-called feed or feed gas, to the membrane material, as well as for the pressure-side discharge of gas(es), the so-called retentate or retentate gas or retentate gas stream or retentate stream, and for the discharge of gas(es) that has permeated through the membrane material, the so-called permeate or permeate gas or permeate gas stream or permeate stream. In the case of drive force generation by purge gas, there is a permeate-side connection option for such a gas. Preferably, the pressure-side concentration, pressure, and temperature profiles are continuous along the respective main flow direction, and the permeate is generated without an intermediate step in a common permeate chamber, such as a housing or permeate tube of the respective membrane separation unit.

[0034] Preferred Membrane separation unit The following embodiments are A. a gas separation module; B. a housing equipped with a gas separation cartridge or several gas separation cartridges connected in series, wherein in the embodiment with several gas separation cartridges connected in series the membrane separation unit is preferably designed such that either the retentate gas outlet of the respective gas separation cartridge is directly connected to the gas inlet of the respective downstream gas separation cartridge by means of a gas line and the permeates of all gas separation cartridges accumulate in a directly communicating gas space, e.g. the housing space, or the retentate gas outlet of the respective gas separation cartridge is connected to the gas inlet of the respective downstream gas separation cartridge by means of a communicating gas space, such asthe housing space, and each cartridge has a permeate collection tube which is directly connected to the permeate collection tube of the respective downstream gas separation cartridge by means of a gas line. C. Several gas separation modules connected in series, wherein the retentate gas outlet of the respective gas separation module is directly connected to the gas inlet of the respective downstream gas separation module by means of a gas line, and the membrane separation unit is designed, e.g., by means of a permeate tube of the respective membrane separation unit, such that the permeates of all gas separation modules of the membrane separation unit are combined. D. Several housings connected in series, equipped with one gas separation cartridge or several gas separation cartridges connected in series, wherein each individual housing is preferably as for embodiment B.The described design includes the serially connected housings, such that the retentate gas outlet of each housing is directly connected to the gas inlet of the next downstream housing by means of a gas line, and the membrane separation unit is designed, for example, by means of a permeate tube of the respective membrane separation unit, so that the permeates of all housings of the membrane separation unit are combined.

[0035] Preferred gas separation cartridges and housings equipped with one or more serially connected gas separation cartridges are disclosed in EP 3307424 B1.

[0036] Gas separation modules differ from Gas separation cartridges,that they represent a complete separation unit, including a pressure-resistant housing. Cartridges, on the other hand, are inserted into separate, pressure-resistant housings, preferably housings permanently installed in the separation system. A single cartridge or several cartridges connected in series can be inserted into the housing. Cartridges have the advantage that their replacement costs are lower than those of modules, since the expensive, pressure-resistant housing does not need to be replaced as well.

[0037] While small-volume cartridges or modules are typically used in biogas upgrading, large-volume cartridges or modules are required for applications such as natural gas purification to handle large gas volumes. Furthermore, this application requires cartridges and modules capable of operating at higher feed gas pressures, preferably from 30 to 100 bar. Gas separation modules and cartridges can contain flat membranes, which are, for example, wound around a centrally located permeate tube.

[0038] In addition, there are cartridges or modules containing hollow fiber membranes. Examples of this can be found in US 3422008, US 3455460, US 3475331, US 4207192, US 4210536, US 4220489, US 4430219, US 4631128, US 4715953, US 4865736, US 4881955, US 5084073, US 5160042, US 5299749, US 5411662, US 5702601, US 5837032, US 5837033, US 5897729, US 7410580, US 7998254, US 8747980, US 8778062.

[0039] In principle, all membrane separation units known to those skilled in the art can be used within the scope of the present invention. Preferred membrane separation units are described in US 2016 / 0151744, US 10,933,378 and US 2018 / 0221824.

[0040] A membrane separation stage according to the invention comprises a "membrane block" or several "membrane blocks", wherein the membrane block or membrane blocks each have several connected in parallel Membrane separation units Each membrane block of a membrane separation stage according to the invention preferably comprises at least two, more preferably more than five, and most preferably more than ten membrane separation units. The number of membrane separation units per membrane block depends on the gas sources and, in particular, the volume of gas to be processed. The use of several hundred membrane separation units is possible in the field of gas separation with membranes.

[0041] The system according to the invention also includes a "Gas distribution".Preferably, the gas distribution is designed such that the feed gas flows are supplied to the membrane separation units of the membrane block or the respective membrane blocks by means of the gas distribution in such a way that they flow towards each other in a pipeline within a membrane block and / or flow towards each other in one or more pipelines that connect the membrane blocks of a membrane separation stage.

[0042] "Flowing towards each other in a pipeline" This includes the following embodiments (non-exhaustive list): Two gas streams flow towards each other in one and the same pipe. Two connecting lines are connected to a gas inlet of a membrane separation unit of a membrane block of a membrane separation stage according to the invention. Two feed gas streams flow towards each other through these two connecting lines and meet at the gas inlet. In a distribution line according to the invention, which contains branches, two feed gas streams flow towards each other and meet between two branches or meet at a branch. In a gas line according to the invention, which connects several membrane blocks of a membrane separation stage and therefore has branches to the respective membrane blocks, two feed gas streams flow towards each other and meet between two branches or at a branch.

[0043] Particularly preferably, the feed gas streams are supplied to the membrane separation units of the membrane block or the respective membrane blocks by means of the gas distribution in such a way that at least two membrane separation units of a membrane block, particularly preferably at least two membrane separation units of several membrane blocks of a membrane separation stage, and most preferably at least two membrane separation units in all membrane blocks of a membrane separation stage, are supplied with gas streams that differ in their composition.

[0044] In the two previously described preferred embodiments, the connection points of the first feed gas line (7) and the second feed gas line (8) are therefore, particularly preferably, arranged independently of each other in such a way as to that the first feed gas stream and the second feed gas stream flow towards each other within a membrane block (1) or several membrane blocks (1) of the membrane separation stage, preferably in one or more distribution line(s) (4) and / or in connecting line(s) (18) and / or within the pipeline(s) that connect(s) the membrane blocks (1) of the membrane separation stage, preferably within the pipeline(s) (19a, 19b, 20a, 20b), and / or that in a membrane block (1), preferably in several membrane blocks (1), particularly preferably in all membrane blocks (1), at least two different membrane separation units (2) of the membrane separation stage are supplied with gas streams which differ in their composition.

[0045] The gas distribution system according to the invention is preferably designed such that the feed gas streams, as described above, flow towards each other, so that there are contact points in the system according to the invention where the feed gas streams supplied to the gas distribution system meet. At these contact points, some mixing of the feed gas streams can occur. Preferably, according to the invention, this mixing should be largely prevented and / or controlled. This can be achieved by suitable, supplementary, design measures in the system according to the invention at the potential contact points. Preferred design measures include reducing the pipe cross-sections and / or lengthening the pipe sections and / or introducing static mixers and / or using pigs in the gas lines. Passive pigs, i.e., pigs whose position in the gas lines of the gas distribution system is determined by the properties of the feed gas streams, can be used.whose pressure or volume flow is controlled, or actively controlled pigs, i.e., pigs whose position in the gas distribution pipelines is determined, e.g., by means of a magnet, independently of the feed stream characteristics, are used. Passive pigs are preferred.

[0046] The permeate streams generated in the membrane separation units of a membrane block can are completely combined into a permeate gas stream and then extracted, further processed or discarded, or are partially combined, resulting in several permeate gas streams which are then independently extracted, further processed or discarded, or are partially combined, resulting in one or more permeate gas streams which are then independently extracted, further processed or discarded, and are partially extracted, further processed or discarded individually, or are all individually extracted, further processed or discarded.

[0047] Preferably, the permeate gas streams are combined such that the number of resulting permeate gas streams corresponds to the number of feed gas streams and the composition of the permeate gas streams is maximally different. Particularly preferably, all permeate gas streams from the membrane separation units of a membrane block to which an identical feed gas stream was supplied are combined. This results in maximally different permeate gas streams, as will be shown in Example 1. If mixed gas streams from different feed gas streams are supplied to some membrane separation units of a membrane block, the permeate streams obtained in these membrane separation units are preferably divided, and the partial streams are each combined with one of the previously described permeate gas streams obtained from the membrane separation units to which a pure feed gas stream was supplied, as will be shown in Example 2.

[0048] The same procedure can be applied to the retentate flows. This results in a very high degree of flexibility for the apparatus and method according to the invention with regard to the gas flows obtained from a single system.

[0049] Preferred embodiments of the inventive system and method, as well as the general inventive principle, are / will be explained in more detail below with reference to the specific embodiments shown in Figures 1 to 11.

[0050] In a first preferred embodiment, the membrane separation stage according to the invention comprises a membrane block (1) or several membrane blocks (1), each with a distribution line (4) with several branches (5), and feed lines (6), wherein each feed line (6) connects a branch (5) to a gas inlet (3) of a membrane separation unit (2), and the first feed gas line (7) and second feed gas line (8) are connected separately and independently of each other, preferably at points as far apart as possible in terms of the flow path, to the distribution line(s) (4) and / or branches (5), particularly preferably to the respective opposite ends of the distribution line(s) (4).

[0051] An example of this first preferred embodiment of the system or method according to the invention is shown in Figure 1This is shown. This comprises a membrane block (1) comprising several parallel-connected membrane separation units (2 1 ) to (2 n ), wherein the index n corresponds to the consecutive number and the number n to the number of parallel-connected membrane separation units of the membrane block (1), each with a gas inlet (3 1 ) to (3 n ). The gas inlets (3 1 ) to (3 n ) of the membrane separation units (2 1 ) to (2 n ) are connected to each other by means of a gas distribution system according to the invention.

[0052] The gas distribution includes a distribution line (4) with several branches (5), supply lines (6 1 ) to (6 n ) which connect the respective branches (5) to the gas inlets (3 1 ) to (3 1 ) of the membrane separation units (2 1 ) to (2 n ),

[0053] and is in Figure 1designed such that the first feed gas line (7) and the second feed gas line (8) are connected separately to the opposite ends of the distribution line (4).

[0054] As a variation of Figure 1 The first feed gas line (7) and / or the second feed gas line (8) can be connected separately to the distribution line (4) or a branch (5) at a different location, the connection points preferably being as far apart as possible in terms of the flow path. It is particularly preferred that the first feed gas line (7) and / or the second feed gas line (8) are each connected to one end of the distribution line (4).

[0055] If the inventive method is used in a plant according to Figure 1As implemented, in the membrane block (1) according to the invention, the first and the second feed gas streams, which differ in their composition, flow towards each other in the distribution line (4) and meet there. Mixing of the gas streams only takes place at the point where the two gas streams meet.

[0056] To illustrate the basic principle of the invention, the following example is considered under simplifying assumptions. The essential simplifying assumptions include: a symmetrical and identical design of all repeating apparatus sections; the pressure loss during the flow of the two different feed gas streams does not depend on density, viscosity, and temperature; the pressure-side pressure loss for all membrane separation units is identical

[0057] At the same pressure and volume flow rate of the first and second feed gas streams, the two gas streams meet in the middle of the distribution line (4) in this example. This means that the first feed gas stream is fed to the membrane separation units (2 1 ) and (2 2 ) and separated there into retentate streams and permeate streams. Similarly, the second feed gas stream is fed to the membrane separation units (2 n-1 ) and (2 n ) and separated there into retentate streams and permeate streams, which differ in composition from the permeate and retentate gas streams generated in the membrane separation units (2 1 ) and (2 2 ). A mixture of the first and second feed gas streams may be fed to further membrane separation units arranged in the middle of the membrane block (1). If, for example, the pressure drops, the retentate and permeate streams are separated in the membrane separation units (2 1 ) and (2 2 ).If the pressure or volume flow rate of the first feed gas stream changes, the point where the two feed gas streams meet in the distribution line (4) shifts towards the end of the distribution line where the first feed gas stream is supplied. As a result, the second feed gas stream is now supplied to more membrane separation units and the first feed gas stream to fewer membrane separation units.

[0058] Preferably, the mixing of the different gas flows in the distribution line (4) is reduced to the desired level or prevented at potential contact points between the feed gas flows by reducing the cross-sectional areas of the pipes and / or lengthening the pipe sections and / or introducing static mixers and / or using pigs between the different gas flows in the distribution line (4). Passive pigs are preferably used.

[0059] The retentate streams from the membrane separation units (2 1 ) to (2 1 ) are in the process and the plant according to Figure 1The retentate gas is fed in retentate gas lines (91) to (9n) into a retentate gas collecting pipe (11). At its first end, located near the membrane separation unit (21), a first retentate gas stream, enriched mainly with the retentate gas from the first feed gas stream, is obtained by adjusting the withdrawal rate and is fed to a first retentate gas outlet (12). At the second end of the retentate gas collecting pipe (11), located near the membrane separation unit (2n), a second retentate gas stream, enriched mainly with the retentate gas from the second feed gas stream, is obtained and is fed to a second retentate gas outlet (13).

[0060] Similarly, the permeate flows from the membrane separation units (2 1 ) to (2 n ) are transferred to permeate gas lines (10 1 ) to (10 n ) in the membrane block (1) in Figure 1a permeate gas collection tube (14). At its first end, located near the membrane separation unit (2 1 ), a first permeate gas stream, enriched mainly with the permeate gas of the first feed gas stream, is obtained by appropriately adjusted withdrawal rates and is fed to the first permeate gas outlet (15). At the second end of the permeate gas collection tube (14), located near the membrane separation unit (2 n ), a second permeate gas stream, enriched mainly with the permeate gas of the second feed gas stream, is obtained and is fed to the second permeate gas outlet (16).

[0061] Similar to the distribution line (4), supplementary measures can also be implemented in the retentate collection pipe (11) at the potential contact points of the retentate streams from the various membrane separation units, particularly at the contact point where the retentate streams mainly enriched with the retentate gas from the first feed gas stream meet the retentate streams mainly enriched with the retentate gas from the second feed gas stream, in order to minimize or prevent mixing of the respective streams or to adjust the corresponding withdrawal rates. Suitable measures include reducing the pipe cross-sections and / or lengthening the pipe sections and / or using pigs, preferably actively controlled pigs.

[0062] Similarly, supplementary measures can also be implemented in the permeate collection tube (14) at the potential contact points of the permeate streams of the various membrane separation units, in particular at the contact point where the permeate streams mainly enriched with the permeate gas of the first feed gas stream meet the permeate streams mainly enriched with the permeate gas of the second feed gas stream, in order to minimize or prevent mixing of the respective streams or to adjust the corresponding withdrawal quantities.

[0063] Suitable measures include reducing the cross-sectional areas of the pipes and / or lengthening the pipe sections and / or using pigs, preferably actively controlled pigs.

[0064] The adjustment of the withdrawal rates in the permeate or retentate streams can also be achieved, for example, via corresponding valves in the retentate gas lines (9) and / or in the permeate gas lines (10) and / or in the retentate collecting pipe (11) and / or in the permeate collecting pipe (14) and / or in the first retentate gas outlet (12) and / or in the second retentate gas outlet (13) and / or in the first permeate gas outlet (15) and / or in the second permeate gas outlet (16) and / or in the embodiment described below. Figure 3 , in the retentate connecting lines (32) and / or in the permeate connecting lines (33). Preferably, valves are used for this purpose in one permeate and all retentate gas lines, or more preferably in all permeate and all retentate gas lines. Most preferably, controllable valves are used for this purpose in all permeate and all retentate gas lines.

[0065] In a second preferred embodiment, the membrane separation stage according to the invention comprises a membrane block (1) or several membrane blocks, each with several connecting lines (18) which each connect the gas inlet (3) of a membrane separation unit (2) with the gas inlet(s) (3) of the membrane separation unit(s) (2) adjacent in the membrane block (1), and the first feed gas line (7) and the second feed gas line (8) are each connected separately and independently to a gas inlet (3) of a membrane separation unit (2) or several gas inlets (3) of membrane separation units (2) and / or to a connecting line (18) or several connecting lines (18).

[0066] An example of this second preferred embodiment of the inventive system and method is shown in Figure 2The membrane block (1) shown therein comprises several parallel-connected membrane separation units (2 1 ) to (2 n ), where the index n corresponds to the consecutive number and the number n to the number of parallel-connected membrane separation units of the membrane block (1), each with a gas inlet (3 1 ) to (3 n ). The membrane separation units (2 1 ) to (2 n ) are connected to each other by means of a gas distribution system according to the invention.

[0067] In the facility or procedure according to Figure 2 The gas distribution system comprises connecting lines (18), each of which connects the gas inlet (3) of a membrane separation unit (2) to the gas inlets (3) of both adjacent membrane separation units, or, in the case of membrane separation units (21) and (2n) arranged at the respective ends of a membrane block (1), to the gas inlet (3) of an adjacent membrane separation unit. The feed gas line (7) is in Figure 2The gas inlet (3 1 ) and the feed gas line (8) are connected to the gas inlet (3 n ). From there, the first and second feed gas streams, flowing towards each other through the connecting lines (18), are distributed to the membrane separation units arranged between the membrane separation units (2 1 ) and (2 1 ).

[0068] In its function, the membrane block corresponds to Figure 2 the membrane block Figure 1 with the difference that the branches (5) of the plant consist of Figure 1 , in Figure 2 are integrated into the gas inlets (3). In the embodiment according to Figure 2 the in Figure 1 The branches (5), supply line (6), and gas inlets (3), which are attached as independent components, are structurally integrated as part of the pressure housing of the respective membrane separation unit. The explanations of the basic principle of the invention are as follows: Figure 1 This also applies to the embodiment according to Figure 2 similar to.

[0069] The embodiment according to Figure 2 This can be modified within the scope of the present invention. For example, it is possible not to connect feed gas line (7) and / or feed gas line (8) to the gas inlets (31) and (3n) of the membrane separation units (21) and (21), but instead to gas inlets of interposed membrane separation units, e.g., to the gas inlets (32) and / or (3n-1). In this case, the first feed gas stream would be routed via a connecting line (18) from the gas inlet (32) to the gas inlet (31) of the membrane separation unit (21) and via another connecting line (18) to the gas inlet (33) of the membrane separation unit (23). In this embodiment, the first feed gas stream would therefore be separated in the membrane separation units (21) and (22).

[0070] Another modification of the embodiment according to the invention Figure 2is designed such that feed gas line (7) and / or feed gas line (8) are not connected to the gas inlets (3 1 ) or (3 n ) of the membrane separation units (2 1 ) and (2 n ), but one or both feed gas lines are connected to connecting line (18), e.g. the feed gas line (7) can be connected to the connecting line (18) between the gas inlets of the membrane separation units (2 1 ) and / or (2 1 ).

[0071] According to the invention, preferred embodiments of the apparatus and the method are those that generate the least possible mixing of the feed streams in order to supply each individual membrane unit with the feed streams in as close as possible to their original composition. Therefore, at potential contact points of the feed gas streams, the mixing of the feed gas streams is preferably reduced or adjusted to the desired level by reducing the cross-sectional areas of the connecting line (18) and / or by lengthening the sections of the connecting line (18) and / or by introducing static mixers and / or by using pigs between the different gas streams in the connecting line (18). Passive pigs are preferably used.

[0072] The retentate and permeate-side configuration of the plant according to the invention according to Figure 2 , i.e., the further processing of the retentate and permeate streams according to the invention is carried out analogously as for Figure 1described.

[0073] Further variations can be easily found by a person skilled in the art using the principle according to the invention.

[0074] The inventive system and method therefore particularly preferably comprise a membrane block (1) comprising a gas distribution system, wherein the gas distribution system in the respective membrane block (1) includes connecting lines (18) which each connect a gas inlet (3) of a membrane separation unit (2) to the gas inlet(s) (3) of the adjacent membrane separation unit(s) (2) in the membrane block (1). The feed gas lines are each connected separately and independently to a gas inlet (3) of a membrane separation unit (2) or several gas inlets (3) of membrane separation units (2) and / or to a connecting line (18) or several connecting lines (18). Preferably, the two feed gas streams are fed to the individual membrane separation units via the connecting lines in a converging flow.

[0075] Furthermore, it is advantageous and desirable to avoid excessive pressure loss in the gas distribution system. Finally, minimizing the equipment and operational effort required for controlling and regulating the system is beneficial. The embodiments shown in Figures 1 and 2 exhibit all these advantages and are therefore particularly preferred.

[0076] In a further, preferred embodiment of the invention, the principle of combining branches (5) and supply lines (6), which was illustrated above using the example of the Figure 2 as explained, transferred to the retentate and / or permeate processing system. Instead of, as in as in Figures 1 and 2As shown, to connect the retentate flows of the membrane separation units (2) of a membrane block (1) to a retentate gas collecting pipe (11) via retentate gas lines (9), in this embodiment the retentate gas outlets (30) of the membrane separation units (2) are connected to retentate connecting lines (32). The retentate gas outlets (12) and (13) are connected to a retentate gas outlet (30) or to a retentate connecting line (32). Preferably, the retentate gas outlet (12) is connected to the retentate gas outlet (30) or structurally to a retentate gas outlet or a retentate connecting line in its vicinity, and the retentate gas outlet (13) is connected to the retentate gas outlet (30) or structurally to a retentate gas outlet or a retentate connecting line in its vicinity. A corresponding embodiment, in combination with the gas distribution system according to Figure 2 , is in Figure 3 shown. Analogously, the retentate processing system can be used according to Figure 3but also with a gas distribution system to Figure 1 can be combined.

[0077] Analogous to the procedure previously described for the retentate processing system, the permeate processing system can also be used. The present invention encompasses embodiments with a retentate and permeate collecting tube in a membrane block, as well as with retentate and permeate connecting lines in a membrane block, as well as with a retentate collecting line and permeate connecting lines in a membrane block, and with a retentate connecting line and permeate collecting line in a membrane block. Combinations of these embodiments, in which, for example, a portion of the retentate gases from a membrane block is fed to a retentate collecting line and another portion is discharged via retentate connecting lines, are also encompassed by the present invention and are readily apparent to a person skilled in the art. The same applies to corresponding combinations for the permeate flows in the membrane block.

[0078] The previously described systems according to the invention and preferred embodiments thereof can be scaled by increasing or decreasing the number "n" of the parallel-connected membrane separation units (2) in a membrane block (1). In this way, the separation capacity of each membrane block (1) and thus of each membrane separation stage can be adjusted without changing the membrane separation units themselves.

[0079] Alternatively or additionally, the membrane separation units themselves can also be varied, e.g. by adjusting the membrane separation area and / or the selectivity of the membranes and / or the permeability of the membranes.

[0080] It is also possible to use different membranes in the membrane separation units (2) of a membrane block (1). Depending on the composition of the feed gas streams to be separated, it may be advantageous to use membranes optimized for a first feed gas stream in the membrane separation units, in which only or mainly the first feed gas stream is separated, and membranes optimized for a second feed gas stream in the separation stages, in which only or mainly the second feed gas stream is separated.

[0081] Since the gas distribution system according to the invention – as described above – regulates the supply of the feed gas streams or mixtures thereof to the individual separation stages, preferably depending on properties of the feed gas streams, such as the current volumetric flow rate and / or mass flow rate and / or pressure of the respective feed gas stream, it can happen that membrane separation units are supplied with a gas mixture with the first feed gas stream as the main component at one point during operation of the plant or the process, and with a gas mixture with the second feed gas stream as the main component at a later point. Therefore, it is preferred to use the same membranes in all membrane separation units (2) of a separation stage (1).

[0082] Alternatively or additionally, the capacity and selectivity of the membrane separation units can be adjusted by the operating temperature. In a preferred embodiment, the feed gas streams have different inlet temperatures. Precise control of the operating temperature can be used, for example, to achieve target values ​​regarding the composition of one or more retentate and / or permeate gases or the yield of at least one gas component.

[0083] Another preferred embodiment for adjusting the separation capacity of a membrane separation stage according to the invention is shown in Figures 4 and 5. Here, several membrane blocks (1) connected in parallel are used in each membrane separation stage. All previously described membrane blocks can be used. The use of several membrane blocks connected in parallel instead of increasing the size of the membrane blocks themselves, i.e., using four membrane blocks with 10 membrane separation units each instead of one block with 40 membrane separation units connected in parallel, has advantages with regard to pressure control, in particular the avoidance of pressure losses, and a simplified rack design.

[0084] In Figure 4 "o" membrane blocks (1) are after Figure 1used, which are connected in parallel, where the index (o) indicates the number of parallel-connected membrane blocks (1). Each membrane block (1 1 ) to (1 o ) has distribution lines (4 1 ) to (4 o ). The ends of the distribution lines (4 1 ) to (4 o ) located on the side of the membrane separation units (2 1 ) of the respective membrane blocks are connected to each other by gas line (19a). Likewise, the ends of the distribution lines (4 1 ) to (4 o ) located on the side of the membrane separation units (2 n ) of the respective membrane blocks are connected to each other by gas line (19b). In Figure 4 For the sake of simplicity, only the feed gas lines (7) and (8), the distribution lines (41) to (40), and the branches (5) in the respective distribution lines are shown. Supply lines (6) extend from each of the branches (5), as shown in Figure 1 shown, to the individual membrane separation units (2). The in Figure 4The permeate and retentate processing systems, which are also not shown, are preferably implemented as explained above, and particularly preferably as shown in one of Figures 1 to 3.

[0085] The feed gas flows can, as in Figure 4 presented in a non-exhaustive overview of possibilities, such a network of membrane blocks can be supplied in different ways.

[0086] Figure 4a shows a connection and a method in which the first feed gas line (7) is connected to the gas line (19a) on the side of the membrane separation unit (2 1 ) of the first membrane block (1 1 ) and the second feed gas line (8) is connected to the gas line (19b) on the side of the membrane separation unit (2 n ) of the last membrane block (1 o ).

[0087] Figure 4bshows a connection and a method in which the first feed gas line (7) is connected to the gas line (19a) on the side of the membrane separation unit (2 1 ) of the first membrane block (1 1 ) and the second feed gas line (8) is connected to the gas line (19b) on the side of the membrane separation unit (2 1 ) of the first membrane block (1 1 ).

[0088] Figure 4c shows a connection in which the first feed gas line (7) is connected to the gas line (19a) located on the side of the membrane separation unit (2 1 ) and the second feed gas line (8) is connected opposite, i.e. to the gas line (19b) located on the side of the membrane separation unit (2 n ), each between two membrane blocks.

[0089] Figure 4d shows a connection in which the first feed gas line (7) is connected in the middle of the distribution line (4 1 ) and the second feed gas line (8) is connected opposite, in the middle of the distribution line (4 o ).

[0090] In this preferred embodiment, the system according to the invention is particularly preferably characterized by the fact that The membrane separation stage comprises several membrane blocks (1), the gas distribution per membrane block (1) comprises a distribution line (4) with several branches (5) and feed lines (6), wherein each feed line (6) connects a branch (5) to a gas inlet (3) of a membrane separation unit (2), the distribution lines (4) of the respective membrane blocks (1) of the membrane separation stage are connected to each other by means of pipes (19a, 19b), and the first feed gas line (7) and second feed gas line (8), independently of each other, are connected at spatially separated locations to a distribution line (4) or a branch (5) or to a pipe (19a, 19b), wherein the connection points are arranged such that two or more than two branches (5) and / or two or more than two gas inlets (3) are arranged between the connection points of the first feed gas line (7) and the second feed gas line (8).

[0091] In Figure 5"o" membrane blocks are after Figure 2 used, which are connected in parallel. The membrane inlets (3 1 ) of the membrane separation units (2 1 ) of the respective membrane blocks (1 1 ) to (1 o ) (in Figure 5 (indicated by dashed ellipses) are each connected to each other by gas line (20a). Likewise, on the opposite side, the membrane inlets (3 1 ) of the respective membrane blocks (1 1 ) to (1 o ) are each connected to each other by gas line (20b). In Figure 5 For simplicity, only the feed gas lines (7) and (8), as well as the connecting lines (18) and the gas inlets (3), are shown. The in Figure 5 The permeate and retentate processing systems not shown are preferably implemented as explained above, and particularly preferably as shown in one of Figures 1 to 3.

[0092] The feed gas flows can, as in Figure 5, in a non-exhaustive presentation of possibilities, shown, such a network of membrane blocks can be supplied in different ways.

[0093] Figure 5a shows a connection in which the first feed gas line (7) is connected to the distribution line (20a) on the side of the membrane separation unit (2 1 ) of the first membrane block (1 1 ) and the second feed gas line (8) is connected to the distribution line (20b) on the side of the membrane separation unit (2 n ) of the membrane block (1 o ).

[0094] Figure 5b shows a connection in which the first feed gas line (7) is connected to the distribution line (20a) on the side of the membrane separation unit (2 1 ) of the first membrane block (1 1 ) and the second feed gas line (8) is connected to the distribution line (20b) on the side of the membrane separation unit (2 n ) of the first membrane block (1 1 ).

[0095] Figure 5cshows a connection in which the first feed gas line (7) is connected to the connecting line (20a) and the second feed gas line (8) is connected opposite, i.e. to, the connecting line (20b) arranged on the side of the membrane separation unit (2n), respectively between two membrane blocks.

[0096] Figure 5d shows a connection in which the first feed gas line (7) is connected to a connecting line (18) of the first membrane block (1 1 ) and the second feed gas line (8) is connected to a connecting line (18) of the membrane block (1 o ).

[0097] In this preferred embodiment, the system according to the invention is particularly preferably characterized by the fact that The membrane separation stage comprises several membrane blocks (1), the gas distribution in each membrane block (1) comprises connecting lines (18) which each connect the gas inlet (3) of a membrane separation unit (2) with the gas inlet(s) (3) of the adjacent membrane separation unit(s) (2) in the membrane block (1), the membrane blocks (1) of the membrane separation stage are connected to each other by means of pipes (20a, 20b), wherein the pipes (20a, 20b) in each membrane block are each connected to one or more connecting lines (18) and / or one or more gas inlets (3), preferably the pipe (20a) in each membrane block (1) is connected to a connecting line (18) or a gas inlet (3) and the pipe (20b) in each membrane block is connected to a different connecting line (18) or a different gas inlet (3), and the first feed gas line (7) and the second feed gas line (8),independently of one another, at spatially separate locations, are connected to one or more connecting line(s) (18) or to one or more pipeline(s) (20a, 20b), or to one or more gas inlet(s) (3), wherein the connection points are arranged such that two or more than two gas inlets (3) are arranged between the connection points of the first feed gas line (7) and the second feed gas line (8).

[0098] An extension of the embodiment according to the invention Figure 5 will be in Figure 6 shown. In addition to Figure 5 Here, not only are the gas inlets (3 1 ) and (3 n ) of the membrane blocks (1 1 ) to (1 o ) connected to each other by the gas lines (20a) and (20b), but at the level of the membrane separation units, the gas inlets (3 2 ) to (3 n-1 ) of the membrane blocks (1 1 ) to (1 o ) are connected to each other by further gas lines (20) to form a "full grid".

[0099] The gas separation system according to the invention is not limited to the simultaneous separation of two feed gas streams with different compositions. The principle according to the invention can also be extended to multiple feed gas streams.

[0100] Preferably, the system according to the invention comprises one, two or three additional feed gas lines three (21), four and five, wherein the feed gas lines three (21), four and five are suitable for transporting one, two or three additional gas streams that differ in composition from the first and second feed gas streams, and wherein the additional feed gas line(s) three (21), four and five are connected to the gas distribution system in such a way that the gas streams three (21) or three (21) and four or three (21), four and five can be supplied to the membrane separation units by means of the gas distribution system.

[0101] In a first preferred embodiment, the additional feed gas lines are connected to one or more distribution lines (4), preferably between the connections of the feed gas lines (7) and (8). An example of such an embodiment, with an additional third feed gas line (21), is shown in Figure 7a ) shown.

[0102] In a second and third preferred embodiment, the additional feed gas lines are connected to one or more connecting lines (18) and / or one or more gas inlets (3). Preferably, the connection point(s) are located on one or more connecting lines (18) and / or gas inlets (3) arranged between the connections of the first feed gas line (7) and the second feed gas line (8), which differ from the gas inlets (3) to which the first feed gas line (7) and the second feed gas line (8) are connected, respectively. Particularly preferably, the additional feed gas line(s) are connected to one of the gas inlets (32) to (3n-1) or to a connecting line (18) arranged between them. Examples of such embodiments, with an additional third feed gas line (21), are shown in Figures 7b) and 7c).

[0103] In a further preferred embodiment, several membrane blocks (1) according to the invention, to which two feed gas lines through which feed gases with different compositions flow are connected, are combined together.

[0104] In a preferred embodiment, the membrane blocks can be linearly combined, i.e., interconnected, with each membrane block (1 1 ) to (1 o ), where o corresponds to the consecutive number of the respective membrane block, being supplied with two feed gas streams. An example of such a system is shown in Figure 8 The feed gas lines (7) and (8) are shown here connected to the distribution line (4 1) of a first membrane block (1 1). This first membrane block (1 1) is combined with a second membrane block (1 2), with the feed gas lines (8) and (21) connected to the distribution line (4 2) of the second membrane block (1 2). Such a system can be extended as needed for additional feed gas flows.

[0105] In a further preferred, alternative embodiment, several membrane blocks (1 1 ) to (1 o ) according to the invention can be combined, i.e., interconnected, to form a ring circuit, wherein preferably each membrane block (1 1 ) to (1 o ) is connected to two feed gas lines. An example of such an arrangement is shown in Figure 9 As shown, three membrane blocks (11), (12), and (13) are combined with distribution lines (41), (42), and (43) to form a ring circuit. The feed gas lines (7) and (8) are connected to distribution line (41), the feed gas lines (7) and (21) to distribution line (42), and the feed gas lines (8) and (21) to distribution line (43). Such ring circuits can be extended by adding further membrane blocks according to the invention, e.g., to a 4-way or 5-way configuration.

[0106] It is also possible to combine the embodiments shown in Figures 7 to 9. For example, in the ring circuit made of Figure 9 a fourth feed gas line is supplied to the distribution line (4 1 ), between the connections of the feed gas lines (7) and (8).

[0107] For simplicity, Figures 7, 8, and 9 show only the feed gas lines (7), (8), and (21), as well as the distribution lines (41) to (43) and the branches (5). Supply lines extend from each branch, as shown in Figure 1 shown, to the individual membrane separation units. The ones in the Figures 7, 8 and 9 The permeate and retentate processing systems, which are also not shown, are preferably implemented as explained above, and particularly preferably as shown in one of Figures 1 to 3, and are connected to each other analogously to the distribution lines.

[0108] The embodiments shown in Figures 8 and 9 can of course also be implemented with membrane blocks from Figures 2 and 3, i.e., with several connecting lines (18) per membrane block. Corresponding embodiments can be easily derived by a person skilled in the art based on the teaching described above according to the invention.

[0109] The inventive system and method, in the general embodiment described above as well as in all preferred embodiments, can comprise one or more valves or other control devices in one or more distribution lines and / or in one or more supply lines and / or in one or more connecting lines, with which the gas supply to the individual gas inlets of the membrane separation units can be controlled or influenced.

[0110] The system can be controlled, for example, by means of the valves or other control devices, or be designed in such a way that one or more membrane separation units can be switched on or off when the volume of gas supplied in the feed gas line changes.

[0111] Shut-off and / or needle valves can be used as valves. However, the gas flow in the gas distribution system can also be influenced and / or controlled via other regulators such as reducers, e.g., orifice plates.

[0112] Particularly in embodiments with distribution lines and / or connecting lines, the distribution system according to the invention can largely or completely self-regulate, as the feed flows converge, e.g., via the volumetric flow rate and / or mass flow rate and / or the pressure of the feed gas flows, without the need for controllable valves within a diaphragm block. Compared to a gas distribution system controlled solely by valves, the number of costly controllable valves can thus be significantly reduced. Therefore, the system according to the invention preferably contains valves for controlling the gas flows only in some, or, more preferably, in none of the distribution line(s) and / or supply line(s) and / or connecting line(s). In another preferred embodiment, however, the diaphragm separation units contain simple manual valves to allow for the rapid separation of a defective diaphragm from the remaining diaphragms in the event of damage.

[0113] The permeate and retentate streams obtained in the membrane blocks according to the invention are preferably fed, as shown in Figures 1 to 3, to a permeate and a retentate processing system per membrane block, respectively. The permeate and retentate processing systems can comprise retentate and / or permeate collecting tubes, as shown in Figures 1 and 2. Alternatively, they can, as shown in Figure 3 The figures show retentate and / or permeate connecting lines between the retentate and permeate outlets of the respective membrane separation units of the respective membrane blocks. Combinations, e.g., the use of retentate connecting lines and permeate collecting tubes, as shown in Figure 3 The ones shown are also possible.

[0114] The retentate and / or permeate streams are fed to the discharge lines via the retentate and / or permeate collecting pipes and / or the retentate and / or permeate connecting lines. In a first preferred embodiment, two locations, preferably two locations as far apart as possible, and particularly preferably both ends of a collecting pipe, are connected to discharge lines, as shown in Figures 1 and 2. This makes it possible to discharge permeate and / or retentate streams, consisting mainly of the permeate and / or retentate gas from the first feed stream, from the discharge lines located near the membrane separation unit (2 1 ). Permeate and / or retentate streams, consisting mainly of the permeate and / or retentate gas from the second feed stream, can be discharged via the discharge lines located near the membrane separation unit (2 n ). The same technical effects can be achieved when using retentate and / or retentate gas from the second feed stream.Permeate connecting lines can be used instead of retentate or permeate collecting pipes. In this case, a drain line near the retentate gas outlet (30 1 ) of the membrane separation unit (2 1 ) is preferably connected to a retentate gas outlet of a membrane separation unit or to a connecting line, and a second drain line near the retentate gas outlet (30 n ) of the membrane separation unit (2 n ) is connected to a gas outlet of a membrane separation unit or to a connecting line. Analogous configurations, e.g., for the permeate flows, are easily implemented by a person skilled in the art.

[0115] Additional discharge lines can be connected, for example, in the middle of the retentate or permeate collecting tubes, or, when using retentate or permeate connecting lines, to a connecting line or a gas outlet of the membrane separation units (2 2 ) or (2 n-1 ), in order to obtain, for example, permeate or retentate streams that consist essentially of a mixture of the permeate or retentate gases from the first and second feed streams. Preferably, such additional discharge lines are connected in the central region of the membrane blocks (1).

[0116] The adjustment of the withdrawal quantities in the permeate or retentate streams can also be achieved, for example, via appropriate valves in the retentate gas lines (9) and / or the permeate gas lines (10) and / or the retentate collecting pipe (11) and / or the permeate collecting pipe (14) and / or the first retentate gas outlet (12) and / or the second retentate gas outlet (13) and / or the first permeate gas outlet (15) and / or the second permeate gas outlet (16) and / or in the embodiment according to Figure 3 the retentate connecting lines (32) and / or permeate connecting lines (33). Preferably, valves are used for this purpose in one permeate and all retentate gas lines, or more preferably in all permeate and all retentate gas lines. Controllable valves are most preferably used for this purpose in all permeate and all retentate gas lines.

[0117] In an alternative, equally preferred embodiment, the permeate or retentate collection pipe is connected to a discharge pipe at only one point. In this case, all permeate or retentate flows are combined in the respective collection pipe and withdrawn from the system as a single, combined mixed flow. The same technical effects can be achieved by using retentate or permeate connecting pipes instead of retentate or permeate collection pipes. In this case, the single discharge pipe is connected to a retentate or permeate connecting pipe or to a retentate or permeate outlet of a membrane separation unit within a membrane block. Such configurations are easily implemented by a person skilled in the art. It is also possible to connect several retentate or permeate discharge pipes into a single pipe to achieve the same technical effect.

[0118] In another, alternative, and also preferred embodiment, it is possible for the permeate and retentate collecting pipes to each be connected to a drain line at only one point. In this case, all permeate and retentate flows are combined in the respective collecting pipe and drawn off the system as a single mixed flow. The same technical effects can be achieved by using retentate and permeate connecting pipes instead of retentate and permeate collecting pipes. In this case, the single drain line is connected to a retentate or permeate connecting pipe or to a retentate or permeate outlet of a membrane separation unit (2 1 ) or a membrane block. Such configurations are easy for a person skilled in the art to implement. It is also possible to connect several retentate or permeate drain lines to a single line to achieve the same technical effect.

[0119] Particularly preferred in the plants and processes according to the invention are Retentate streams, preferably all retentate streams, from the membrane separation units (2) of a membrane block (1) are supplied to a retentate gas collecting tube (11) by means of retentate gas lines (9), wherein the retentate gas collecting tube (11) is connected to at least one first retentate gas outlet (12), preferably at least two retentate gas outlets (12) and (13), through which one or more retentate gas streams are discharged from the membrane separation stage in which they were generated, and / or permeate streams, preferably all permeate streams, from the membrane separation units (2) of a membrane block (1) are supplied to a permeate gas collecting tube (14) by means of permeate gas lines (10), wherein the permeate gas collecting tube (14) is connected to at least one first permeate gas outlet (15), preferably at least two permeate gas outlets (15) and (16), through which one or more permeate gas streams are discharged from the membrane separation stage. They will be removed from the area where they were produced.

[0120] The following are also particularly preferred in the plants and processes according to the invention: Retentate streams, preferably all retentate streams, of the membrane separation units of a membrane block are supplied by means of retentate connecting lines between the retentate gas outlets of one or more retentate discharge lines, through which one or more retentate gas streams are discharged from the membrane block, wherein the system in this case comprises retentate connecting lines (32) between the retentate gas outlets (30) of the membrane separation units (2) of a membrane block (1) of the membrane separation stage, wherein at least one retentate connecting line (32) or at least one retentate gas outlet (30) is also connected to at least one retentate gas discharge (12), preferably in a membrane block (1) of the membrane separation stage one or more retentate connecting lines (32) and / or one or more retentate gas outlets (30) are connected to two retentate gas discharges (12) and (13), and / or permeate streams, preferably all permeate streams,The membrane separation units of a membrane block are supplied with permeate by means of permeate connecting lines between the permeate gas outlets to one or more permeate discharge lines, through which one or more permeate gas streams are discharged from the membrane block, wherein the system in this case comprises permeate connecting lines (33) between the permeate gas outlets (31) of the membrane separation units (2) of a membrane block (1) of the membrane separation stage, wherein at least one permeate connecting line (33) or at least one permeate gas outlet (31) is connected to at least one permeate gas discharge (15), preferably one or more permeate connecting lines (33) and / or one or more permeate gas outlets (31) are connected to two retentate gas discharges (15) and (16) in a membrane block (1) of the membrane separation stage.

[0121] If membrane separation stages with several membrane blocks are used in the inventive system or method, the permeate and retentate streams of the respective membrane blocks of a membrane separation stage are preferably combined to form one or two permeate streams or one or two retentate streams per membrane separation stage. Preferably, all first retentate streams obtained in the first retentate gas outlet (12) of the respective membrane blocks (1) are combined to form a first retentate stream of the membrane separation stage.

[0122] If second retentate streams are also obtained in the second retentate gas outlet (13) of the respective membrane blocks (1), these second retentate streams are preferably combined to form a second retentate stream of the membrane separation stage. An analogous procedure can be followed if further retentate streams are obtained in the respective membrane blocks.

[0123] The permeate flows of the respective membrane blocks (1) of a membrane separation stage are preferably treated analogously to the retentate flows described above.

[0124] The permeate and retentate streams obtained from a membrane separation stage according to the invention can be withdrawn as product streams, further processed, or discarded, wherein at least one permeate and / or retentate stream is withdrawn or further processed as product streams. Particularly preferably, at least two permeate streams or at least two retentate streams are generated in each membrane separation stage, of which at least one is withdrawn or further processed as product streams.

[0125] The system according to the invention can comprise a membrane separation stage or several interconnected membrane separation stages according to the invention, wherein at least one membrane separation stage according to the invention, comprising a membrane block (1) or several membrane blocks (1), which in turn each comprise several parallel interconnected membrane separation units (2), together with a gas distribution system according to the invention, which is designed such that The system comprises connecting lines (18) that directly and immediately connect the gas inlets (3) of two adjacent membrane separation units (2) of a membrane block (1) to each other, and / or one or more distribution lines (4) that contain one or more branches (5), each of which is connected to a gas inlet (3) of a membrane separation unit (2) of a membrane block (1) by means of a separate supply line (6), wherein one or more branches (5) may additionally also have a connection option for a feed gas line, so that a feed gas line and a supply line (6) may be connected to the respective distribution line (4) simultaneously by means of the branch(es) (5), and, if the membrane separation stage comprises several membrane blocks (1), it comprises pipelines, preferably pipelines (19a, 19b, 20a, 20b), that connect the membrane blocks (1) of the membrane separation stage to each other.the first feed gas line (7) and the second feed gas line (8), independently of each other, at spatially separate locations, are connected to a distribution line (4) or a connecting line (18) or a branch (5) or, if present, to a pipeline, preferably a pipeline (19a, 19b, 20a, or 20b), or to a gas inlet (3), wherein the connection points are arranged such that two or more than two branch(es) (5) and / or two or more than two gas inlets (3) are arranged between the connection points of the first feed gas line (7) and the second feed gas line (8), . is used.

[0126] The present invention also includes embodiments in which several membrane separation stages according to the invention are interconnected.

[0127] This shows Figure 10A two-stage circuit in which the two membrane separation stages A and B according to the invention are connected on the retentate side. In the system according to Figure 10 Two feed gas streams, differing in their composition, are supplied to the first membrane separation stage A via feed gas lines (7) and (8), which are preferably configured as in Figure 1 The system is designed as shown and described above. The two permeate streams obtained from the permeate collection tube of the first membrane separation stage A are independently extracted as product streams, further processed, or discarded via permeate gas outlets (15) and (16). The two permeate streams can be treated identically or independently and differently. The two retentate streams obtained from the retentate collection tube of the first membrane separation stage A are fed to the membrane separation stage B as new feed streams via retentate gas outlets (12) and (13). As above. Figure 1As explained, the two retentate streams obtained from the retentate collection tube of the first membrane separation stage differ in their composition. The retentate stream discharged in the retentate gas outlet (12) mainly contains the retentate gas from the first feed stream, and the second retentate stream discharged in the retentate gas outlet (13) mainly contains the retentate gas from the second feed stream. The retentate gases in both retentate streams can be the same or different. If they are the same, the two retentate gas streams still differ in their concentration, i.e., their quantitative composition.

[0128] Since the two retentate streams of membrane separation stage A differ in their composition, the same condition applies to the second membrane separation stage B as to membrane separation stage A, i.e., it is supplied with two feed gas streams, the second feed gas stream differing from the first in its composition. Membrane separation stage B is preferably configured as shown in Figure 1 The setup is shown. The two permeate streams obtained from the permeate collection tube of the second membrane separation stage B are returned to the feed gas lines (7) and (8) via the permeate gas outlets (22) and (23). The two retentate streams obtained from the retentate collection tube of the second membrane separation stage B are either removed as product streams, further processed, or discarded independently of each other via the retentate gas outlets (24) and (25).

[0129] For the operation of a membrane separation unit, a partial pressure difference, and thus generally a pressure difference between the retentate and permeate sides, is necessary. The pressure on the retentate side must be higher than on the permeate side. This can be ensured, for example, by generating a feed gas flow at increased pressure using a compressor, or by creating a vacuum on the permeate side of the membrane, for example, using a vacuum pump. Such technologies are known to those skilled in the art. For the connection according to Figure 10This means that the pressure in the permeate gas lines (22) and (23) is generally lower than in the feed gas lines (7) and (8). The recirculated permeate streams must therefore be compressed in the compression units P1 and P2, respectively, to the pressure of the feed streams in the feed gas lines (7) and (8). The compression units P1 and P2 can be identical or different in design. For example, a compressor can be used in one or both of the permeate gas lines (22) and / or (23). This configuration is preferred if one or both of the Figure 10 The raw gas flows, not shown, are already under sufficient pressure.

[0130] Alternatively, one or both of the permeate streams returned in the permeate gas outlets (22) and (23) can be directed to one of the compression units P1 and P2, respectively, as described in Figure 10raw gas streams not shown are supplied and the resulting mixed stream or the two resulting mixed streams are compressed, thus generating the feed stream or the two feed streams in the feed gas lines (7) and / or (8).

[0131] Alternatively, one or both of the permeate streams returned in the permeate gas lines (22) and (23) can be fed directly to a compressor in the compression units P1 and P2, respectively, which generates one of the two feed streams in the feed gas lines (7) and (8).

[0132] The latter two alternatives are preferred when the raw gas stream(s) have a lower pressure than the feed stream(s).

[0133] Alternatively or additionally, the partial pressure difference can also be generated or increased by a purge gas flow on the permeate side. This procedure is also known to those skilled in the art.

[0134] Devices for increasing the pressure in the permeate gas outlets (15) and (16) and / or (22) and (23) are useful for increasing the driving force, but are less preferred due to the equipment costs.

[0135] Alternatively, but also preferred, one or both of the membrane separation stages A and / or B can be used in Figure 10 also as in the other preferred embodiments discussed above, in particular as Figure 2 or 3 be shown, designed.

[0136] The wiring according Figure 10 It can be varied in several ways. Examples include: The permeate streams obtained from membrane separation stage B can be independently withdrawn, further processed, or discarded as product streams, provided that at least one of the two permeate streams from membrane separation stage A or B, or the retentate streams from membrane separation stage B, is withdrawn or further processed as a product stream; one, preferably both, of the permeate streams obtained from membrane separation stage B is / are returned to the respective original feed stream of membrane separation stage A; and simultaneously, the retentate streams obtained from membrane separation stage B are independently withdrawn, further processed, or discarded as product streams, provided thatthat at least one of the two permeate streams from membrane separation stage A or the retentate streams from membrane separation stage B is withdrawn as a product stream; both permeate streams obtained from membrane separation stage A are fed as feed streams to the second membrane separation stage B; and the two retentate streams obtained from membrane separation stage A are withdrawn, independently of each other, as a product stream, further processed, or discarded.

[0137] Further variations of the 2-stage circuit can be easily found by a person skilled in the art based on the teaching according to the invention.

[0138] The inventive system and method are therefore particularly preferred in that They comprise two membrane separation stages A and B, each comprising one membrane block (1) or several membrane blocks (1), each comprising several membrane separation units (2) connected in parallel, and the gas distribution of the first membrane separation stage A is designed such that it connects the first feed gas line (7) and the second feed gas line (8) to the gas inlets (3) of the membrane separation units (2) of the first membrane separation stage A such that gas streams differing in composition are supplied to at least two different membrane separation units (2) in each membrane block (1) of the membrane separation stage A, and the first membrane separation stage A is designed such thatthat two different retentate streams are obtained in a first retentate gas outlet (12) and a second retentate gas outlet (13) and / or two different permeate streams are obtained in a first permeate gas outlet (15) and a second permeate gas outlet (16), the two retentate streams or the two permeate streams of the first membrane separation stage A are supplied to the second membrane separation stage B as feed streams, and the gas distribution of the second membrane separation stage B is designed such that it connects the first retentate gas outlet (12) and the second retentate gas outlet (13) or the first permeate gas outlet (15) and the second permeate gas outlet (16) to the gas inlets (3) of the membrane separation units (2) of the second membrane separation stage B in such a way that at least two different membrane separation units (2) are supplied to each membrane block (1) of the second membrane separation stage B, which differ in their composition.

[0139] Particularly preferred is the second membrane separation stage B designed such that two different retentate streams are obtained in a first retentate gas outlet (24) and a second retentate gas outlet (25), and / or two different permeate streams are obtained in a first permeate gas outlet (22) and a second permeate gas outlet (23).

[0140] Figure 11 As a further, particularly preferred, embodiment of the invention, a 3-stage interconnection is shown in which three membrane separation stages according to the invention are interconnected in such a way that the two retentate streams of membrane separation stage A are supplied as feed streams to membrane separation stage B and the two permeate streams of membrane separation stage A are supplied as feed streams to membrane separation stage C.

[0141] Two feed gas streams, differing in their composition, are supplied to the first membrane separation stage A via feed gas lines (7) and (8), which are preferably configured as in Figure 1 The configuration is shown. The two permeate streams obtained from the permeate collection tube of the first membrane separation stage A are fed to membrane separation stage C as new feed gas streams via the permeate gas outlets (15) and (16). The two retentate streams obtained from the retentate collection tube of the first membrane separation stage A are fed to membrane separation stage B as new feed streams via the retentate gas outlets (12) and (13). As explained above with reference to Figures 1 and 10, the two retentate gas streams obtained from the first membrane separation stage A differ in their composition. The same applies to the permeate gas streams obtained from the first membrane separation stage A.

[0142] Since the two retentate streams of membrane separation stage A differ in their composition, the same condition applies to the second membrane separation stage B as to membrane separation stage A, i.e., it is supplied with two feed gas streams, the second feed gas stream differing from the first in its composition. Membrane separation stage B is preferably configured as shown in Figure 1 The two retentate streams obtained from the retentate collection tube of the second membrane separation stage B are independently extracted as product streams, further processed, or discarded via the retentate gas outlets (24) and (25). The two permeate streams obtained from the permeate collection tube of the second membrane separation stage B are returned to the feed gas lines (7) and (8) respectively via the permeate gas outlets (22) and (23).

[0143] Since the two permeate streams of membrane separation stage A differ in their composition, the same condition applies to the third membrane separation stage C as to membrane separation stage A, i.e., it is supplied with two feed gas streams, the second of which differs from the first in its composition. Membrane separation stage C is also as in Figure 1 The setup is shown. The two permeate streams obtained from the permeate collection tube of the third membrane separation stage C are independently extracted as product streams, further processed, or discarded via the permeate gas outlets (26) and (27). The two retentate streams obtained from the retentate collection tube of the third membrane separation stage C are returned to the feed gas lines (7) and (8) respectively via the retentate gas outlets (28) and (29).

[0144] Alternatively, but also preferred, one, two or all three membrane separation stages A, B and / or C can be used in Figure 11also as in the other preferred embodiments discussed above, in particular as Figure 2 or 3 be shown, designed.

[0145] For the wiring according to Figure 11 The same applies as for Figure 10 This means that the pressure in the permeate gas lines (22) and (23) and in the retentate gas lines (28) and (29) is lower than in the feed gas lines (7) and (8). The recirculated gas flows must therefore be compressed in the compression units P1 and P2, respectively, to the pressure of the feed gas flows in the feed gas lines (7) and (8). The compression units P1 and P2 can be of the same or different designs.

[0146] Preferably, the permeate gas outlet (22) is combined with the retentate gas outlet (28) and fed to the compression unit P1 via a further gas line. The permeate gas outlet (23) is preferably combined with the retentate gas outlet (29) and fed to the compression unit P2 via a further gas line.

[0147] A compressor can be arranged in one or both of the gas lines supplied to the compression units P1 and P2, respectively. This configuration is preferred if one or both of the gas lines supplied to the compression units P1 and P2 are located in the same building. Figure 11 The raw gas flows, not shown, are already under sufficient pressure.

[0148] Alternatively, one or both of the gas streams returned in the gas lines leading to compression units P1 and P2 can be directed to one of the compression units P1 and P2, respectively. Figure 11raw gas streams not shown are supplied and the resulting mixed stream(s) are compressed to generate the feed stream(s) in the feed gas lines (7) and / or (8).

[0149] Alternatively, one or both of the gas flows returned in the gas lines supplied to the compression units P1 and P2 can be fed directly to a compressor that generates one of the two feed gas flows in the feed gas lines (7) and / or (8).

[0150] The latter two alternatives are preferred when the raw gas stream(s) has / have a lower pressure than the feed stream(s).

[0151] Alternatively, the partial pressure difference can also be generated by a purge gas on the permeate side. This procedure is also known to those skilled in the art.

[0152] Devices for increasing the pressure in the permeate gas outlets (15) and (16) and / or (22) and (23) and / or (26) and (27) are useful for increasing the driving force, but are not preferred due to the equipment costs.

[0153] Further variations of the 3-stage circuit can be easily found by a person skilled in the art based on the teaching according to the invention.

[0154] The inventive system and method are therefore particularly preferred in that They comprise three membrane separation stages A, B and C, wherein each of the three membrane separation stages A, B and C comprises one membrane block (1) or several membrane blocks (1), each comprising several membrane separation units (2) connected in parallel, and the gas distribution of the first membrane separation stage A is designed such that it connects the first feed gas line (7) and the second feed gas line (8) to the gas inlets (3) of the membrane separation units (2) of the first membrane separation stage A such that gas streams differing in composition are supplied to at least two different membrane separation units (2) in each membrane block (1) of the membrane separation stage A, and the first membrane separation stage A is designed such thatthat two different retentate streams are obtained in a first retentate gas outlet (12) and a second retentate gas outlet (13), and two different permeate streams are obtained in a first permeate gas outlet (15) and a second permeate gas outlet (16), the two retentate streams of the first membrane separation stage A are supplied to the second membrane separation stage B as feed streams, wherein the retentate gas outlets (12) and (13) are connected to the gas distribution of the second membrane separation stage B, the two permeate streams of the first membrane separation stage A are supplied to the third membrane separation stage C as feed streams, wherein the permeate gas outlets (15) and (16) are connected to the gas distribution of the third membrane separation stage C, the gas distribution of the second membrane separation stage B is configured such thatthat it connects the first retentate gas outlet (12) and the second retentate gas outlet (13) to the gas inlets (3) of the membrane separation units (2) of the second membrane separation stage B in such a way that at least two different membrane separation units (2) are supplied to each membrane block (1) of the second membrane separation stage B, and that the gas distribution of the third membrane separation stage C is designed such that it connects the first permeate gas outlet (15) and the second permeate gas outlet (16) to the gas inlets (3) of the membrane separation units (2) of the third membrane separation stage C in such a way that at least two different membrane separation units (2) are supplied to each membrane block (1) of the third membrane separation stage C, which differ in their composition.

[0155] Particularly preferred is the second membrane separation stage B configured such that two different retentate streams are obtained in a first retentate gas outlet (24) and a second retentate gas outlet (25) and / or two different permeate streams are obtained in a first permeate gas outlet (22) and a second permeate gas outlet (23) and / or the third membrane separation stage C configured such that two different retentate streams are obtained in a first retentate gas outlet (28) and a second retentate gas outlet (29) and / or two different permeate streams are obtained in a first permeate gas outlet (26) and a second permeate gas outlet (27).

[0156] As previously demonstrated using 2- and 3-stage configurations as examples, the membrane separation stages designed according to the invention can be combined to form any type of multi-stage configuration, particularly preferably 2-, 3-, 4- and 5-stage configurations, and most preferably 2-, 3- and 4-stage configurations. Corresponding configurations are known to those skilled in the art for "classic" membrane separation stages to which only a gas stream is supplied for separation. The 3-stage configuration is most preferred within the scope of the present invention.

[0157] In the systems according to the invention, membrane separation stages according to the invention, which separate at least two different feed gas streams, can also be combined with "classic" membrane separation stages that separate only one gas stream into a permeate and a retentate stream. For example, classic membrane separation stages can be used upstream to generate one or more feed gas streams.

[0158] However, it is also possible to use conventional membrane separation stages downstream of a membrane separation stage according to the invention. For example, one of the permeate and / or retentate streams obtained from a membrane separation stage according to the invention could be fed to such a conventional membrane separation stage. Furthermore, as already explained above, it is possible to design the membrane separation stages according to the invention such that only one permeate and / or only one retentate stream is obtained. These permeate or retentate streams can then be further processed in conventional membrane separation stages.

[0159] As already explained for the specific embodiments shown in Figures 10 and 11, the membrane separation stages included in the inventive system and the inventive method require a partial pressure difference between the retentate and permeate sides of the membranes. Therefore, for all embodiments of the present invention, if the feed gas streams of the respective membrane separation stages do not exhibit a sufficient partial pressure difference to the permeate side of the membrane separation stages, a compressor is preferably used in the feed gas line and / or a vacuum pump is used on the permeate side of the membrane. Equally preferred, as an alternative or in combination, purge gas can be supplied to the permeate chamber to increase the partial pressure difference. This is known to those skilled in the art as a sweep. It is particularly preferred that compressors are used only in one or more feed streams upstream of the first separation stage according to the invention.

[0160] The present invention comprises – as already indicated – a method for the simultaneous purification of two or more gas streams which differ in their composition. The method according to the invention is carried out in a plant according to the invention.

[0161] The inventive method particularly preferably comprises the following steps: i) Providing a first feed gas stream, ii) Providing a second feed gas stream which differs in its composition from the first feed gas stream, iii) Supplying the first and the second feed gas streams to a membrane separation stage, wherein the membrane separation stage comprises one or more membrane separation blocks (1), and the membrane separation block (1) or the membrane separation blocks (1) each comprise several membrane separation units (2) connected in parallel, the membrane separation stage comprising a gas distribution system which includes connecting lines (18) which each connect the gas inlets (3) of two adjacent membrane separation units (2) of a membrane block (1), preferably directly and immediately, to one another and / or distribution lines (4) which contain several branches (5) which are each connected by means of separate supply lines (6) to the gas inlets (3) of the individual membrane separation units (2) of a membrane block (1),wherein one or more branch(es) (5) may additionally also have a connection option for a feed gas line, so that a feed gas line and a supply line (6) may be connected to the distribution line (4) simultaneously by means of the branch(es) (5), the membrane separation stage, if it comprises several membrane blocks (1), comprises pipelines, preferably pipelines (19a, 19b, 20a, 20b), which connect the membrane blocks (1) of the membrane separation stage to one another, and wherein the first and the second feed gas streams are supplied, independently of one another, at spatially separated points, to a distribution line (4) or a connecting line (18) or a branch (5), or, if present, to a pipeline or pipelines which connect the membrane blocks (1) of a membrane separation stage to one another, preferably a pipeline or pipelines (19a, 19b, 20a, 20b), or to a gas inlet (3),wherein the connection points of the first and second feed gas streams are arranged such that two or more than two branch(es) (5) and / or two or more than two gas inlets (3) are arranged between the connection points, iv) supplying the first and second feed gas streams by means of the gas distribution to the gas inlets (3) of the membrane separation units (2) of the membrane separation stage, v) separating the gas mixtures supplied to the membrane separation units (2) by means of the gas separation membranes in the membrane separation units (2), into a retentate gas stream and a permeate gas stream, respectively.

[0162] The method of the present invention particularly preferably also comprises the steps: vi) Combining, preferably all, retentate streams of the membrane separation units (2) of a membrane block (1) to form one or more retentate gas streams, and / or vii) Combining, preferably all, permeate streams of the membrane separation units (2) of a membrane block (1) to form one or more permeate gas streams.

[0163] The merging of the permeate and / or retentate streams can, as described above, preferably be carried out by means of permeate and / or retentate collecting lines or via retentate and / or permeate connecting lines between the corresponding gas outlets of the membrane separation units.

[0164] Further preferred process steps will become apparent from the above description of the inventive system and process, as well as the examples and the claims.

[0165] The inventive system and method can be used in particular in processes where the simultaneous separation of several gas streams with different compositions using gas separation membranes is necessary. This is especially true in processes where the gas streams to be separated can fluctuate in their respective volume flows and compositions. This applies particularly to processes using renewable energies, as these are often only available in highly fluctuating quantities. Further examples of applications include, for example...Natural gas fields with different gas sources, which are to be processed in a common gas separation plant instead of in a separate gas separation plant for each gas source, or helium gas sources in which methane is separated from helium in a gas separation plant, the methane is subsequently thermally utilized, and the exhaust gases from the thermal utilization are also to be separated by gas separation. Examples 1 and 2 show that the two gas separations can be carried out much more effectively in a plant according to the invention instead of in two separate gas separation plants. Examples

[0166] For the creation of the examples, process simulation calculations were performed in Aspen Custom Modeller (ACM), according to the model by Scholz et al., "Modeling Gas Permeation by Linking Nonideal Effects", Industrial & Engineering Chemistry Research, 2013, 52, 1079-1088. The model depth used for the simulation from Scholz et al. is as follows: Ideal countercurrent flow of retentate and permeate; constant permeances and therefore constant separation capacities (temperature-independent); consideration of pressure loss; consideration of energy balance; consideration of the Joule-Thomson effect; real gas behavior according to Soave-Redlich-Kwong; neglect of concentration polarization and other non-ideal effects

[0167] The module geometry used is as follows. The outer diameter of the hollow membrane fiber is 415 µm, and the wall thickness of the hollow membrane fibers is 74 µm. The fiber length is 1 m, and the module diameter is 0.16 m. In the examples, one membrane separation unit corresponds to one membrane module in the simulation. The number of fibers is 76,700. The heat transfer coefficient of the fiber is 4 W / (m² < K). In the examples, one membrane separation unit corresponds to one membrane module in the simulation. Example series 1 (Examples 1.1 to 1.9):

[0168] In example series 1, a separation system is implemented accordingly. Figure 1The first feed gas stream A consists of 10 vol% helium (He) and 90 vol% methane (CH₄). The second feed gas stream B consists of 40 vol% CO₂ and 60 vol% N₂. Feed gas streams A and B are fed to a membrane separation stage, consisting of a membrane block (1) with 10 membrane separation units (MTEs) (2 1 - 2 10 ). The permeates and retentates of the respective MTEs are fed via permeate gas lines (10 1 - 10 10 ) to a permeate collection tube (14) and via retentate gas lines (9 1 - 9 10 ) to a retentate collection tube (11). The individual MTEs are identical and contain polyimide hollow fiber membranes which are operated in countercurrent flow. The two feed gas streams A and B are fed at an identical feed gas temperature of 25°C via the feed gas line (7) and (8) to a distribution line (4) at its opposite ends and from there via the supply lines (6 1 - 6 10 ) to the respective MTEs (2 1 - 2 10 ).The pressure of the retentate gas streams is maintained at an identical pressure of 10.00 bara by means of valves in the retentate gas outlets (12) and (13). Due to pressure loss resulting from variations in the flow rates, the pressure of the feed gas streams in the feed lines (7) or (8) varies slightly from 10.08 to 10.1 bara. The compositions, temperatures, flow rates, and pressures of the two feed gas streams A and B are given in Tables 1a and 1b. The pressure of the permeate gas streams is set to 1.01 bara by means of valves in the permeate gas outlets (15) and (16). Under the stated conditions, the respective MTEs exhibit a separation capacity of 40,000 GPU*m² for helium (He), 26,700 GPU*m² for CO₂, 800 GPU*m² for N₂, and 530 GPU*m² for CH₄. Accordingly, the selectivities, i.e., the ratio of the permeances of the membrane used in the MTEs, are 75 for He / CH₄ and 33 for CO₂ / N₂.

[0169] In this example, the sum of the volume flows of both feed gas streams is always 1000 Nm³ / h. However, in the series of examples 1.1 to 1.9, the individual volume flows are changed in such a way that the volume flow of feed stream A increases from example to example and the volume flow of feed stream B decreases by the same amount from example to example.

[0170] In example series 1, the different feed gas streams flow unmixed into the MTEs, and the retentate and permeate gas streams are also drawn off without mixing. This is ensured by appropriate pigs in the distribution line (4) and the permeate collecting pipe (14) and the retentate collecting pipe (11), respectively. The pressure drop across the distribution line (4) and branches (5) is only a few mbar in this example, which means that the feed gas is distributed almost ideally to the MTEs in terms of quantity.

[0171] In example 1.1, due to the low volume flow rate of the feed gas stream A, it is only supplied to the MTE (2 1 ) via feed line (6 1 ), the retentate gas of the MTE (2 1 ) from retentate gas line (9 1 ) is withdrawn exclusively via retentate gas outlet (12) and the permeate gas of the MTE (2 1 ) from permeate gas line (10 1 ) is withdrawn exclusively via the permeate gas outlet (15). Accordingly, the feed gas stream B is supplied to the remaining MTEs (2 2 to 2 10 ) via the feed lines (6 2 to 6 10 ), the retentate gas from the retentate gas lines (9 2 to 9 10 ) is discharged exclusively via the retentate gas outlet (13), and the permeate gas from the permeate gas lines (10 2 to 10 10 ) is withdrawn exclusively via the permeate gas outlet (16). The separation results in all four gas outlets (retentate gas outlets (12) and (13), as well as permeate gas outlets (15) and (16)) achieving the ideal purities and yields at which the product of purity and yield is maximized.

[0172] The compositions, temperature, volume flow rate, pressures and yields of the two permeate streams (15) and (16) and the two retentate streams (12) and (13) obtained in the respective examples 1.1 to 1.9 can be found in Tables 2a to 2d. Table 1a: Feed current A measured in the feed line (7) Example Pressure Temp. Flow He CH 4 # [bar(a)] [°C] [Nm 3< / h] [vol%] [vol%] 1.1 10,08 25 100 10 90 1.2 10,08 25 200 10 90 1.3 10,09 25 300 10 90 1.4 10,09 25 400 10 90 1.5 10,09 25 500 10 90 1.6 10,09 25 600 10 90 1.7 10,1 25 700 10 90 1.8 10,1 25 800 10 90 1.9 10,1 25 900 10 90 Table 1b: Feed current B measured in the feed lines (8) Example Pressure Temp. Flow CO2 N 2 # [bar(a)] [°C] [Nm 3< / h] [vol%] [vol%] 1.1 10,1 25 900 40 60 1.2 10,1 25 800 40 60 1.3 10,1 25 700 40 60 1.4 10,09 25 600 40 60 1.5 10,09 25 500 40 60 1.6 10,09 25 400 40 60 1.7 10,09 25 300 40 60 1.8 10,08 25 200 40 60 1.9 10,08 25 100 40 60 Table 2a: First retentate stream in retentate gas vent (12) Example Pressure Temp. Flow He CH 4 CH4 yield # [bar(a)] [°C] Nm 3< / h] [vol%] [vol%] [%] 1.1 10 24,8 77,7 0,64 99,4 85,7 1.2 10 24,8 155 0,64 99,4 85,7 1.3 10 24,8 233 0,64 99,4 85,7 1.4 10 24,8 311 0,64 99,4 85,7 1.5 10 24,8 388 0,64 99,4 85,7 1.6 10 24,8 466 0,64 99,4 85,7 1.7 10 24,8 544 0,64 99,4 85,7 1.8 10 24,8 621 0,64 99,4 85,7 1.9 10 24,8 699 0,64 99,4 85,7 Table 2b: Second retentate stream in retentate gas vent (13) Example Pressure Temp. Flow CO2 N 2 N2 yield # [bar(a)] [°C] [Nm 3< / h] [vol%] [vol%] [%] 1.1 10 21,8 389 0,40 99,6 71,8 1.2 10 21,8 346 0,40 99,6 71,8 1.3 10 21,8 303 0,40 99,6 71,8 1.4 10 21,8 259 0,40 99,6 71,8 1.5 10 21,8 216 0,40 99,6 71,8 1.6 10 21,8 173 0,40 99,6 71,8 1.7 10 21,8 130 0,40 99,6 71,8 1.8 10 21,8 86,5 0,40 99,6 71,8 1.9 10 21,8 43,2 0,40 99,6 71,8 Table 2c: First permeate stream Permeate gas discharge (15) Example Pressure Temp. Flow He CH 4 He yield # [bar(a)] [°C] [Nm 3< / h] [vol%] [vol%] [%] 1.1 1,01 25,6 22,4 42,5 57,5 95,0 1.2 1,01 25,6 44,7 42,5 57,5 95,0 1.3 1,01 25,6 67,1 42,5 57,5 95,0 1.4 1,01 25,6 89,4 42,5 57,5 95,0 1.5 1,01 25,6 112 42,5 57,5 95,0 1.6 1,01 25,6 134 42,5 57,5 95,0 1.7 1,01 25,6 156 42,5 57,5 95,0 1.8 1,01 25,6 179 42,5 57,5 95,0 1.9 1,01 25,6 201 42,5 57,5 95,0 Table 2d: Second permeate stream Permeate gas discharge (16) Example Pressure Temp. Flow CO2 N 2 CO2 yield # [bar(a)] [°C] [Nm 3< / h] [vol%] [vol%] [%] 1.1 1,01 21,3 511 70,2 29,8 99,6 1.2 1,01 21,3 454 70,2 29,8 99,6 1.3 1,01 21,3 397 70,2 29,8 99,6 1.4 1,01 21,3 341 70,2 29,8 99,6 1.5 1,01 21,3 284 70,2 29,8 99,6 1.6 1,01 21,3 227 70,2 29,8 99,6 1.7 1,01 21,3 170 70,2 29,8 99,6 1.8 1,01 21,3 114 70,2 29,8 99,6 1.9 1,01 21,3 56,8 70,2 29,8 99,6 Example series 2 (Examples 2.1 to 2.8)

[0173] Example series 2 corresponds to example series 1 with the difference that the feed gas streams enter the MTEs less ideally separated and are discharged less ideally as retentate gas and permeate gas. This means that the pig used in the connecting line (4) in example 1 is omitted, and the two gas streams may mix to a small extent at the point where they meet. In example series 2, the meeting of feed gas stream A and feed gas stream B occurs such that 50 Nm³ / h of feed gas stream A and 50 Nm³ / h of feed gas stream B are supplied to the respective MTE via the nearest feed line. This means that for example 2.1, MTE (2 1 ) contains pure feed gas stream A, while MTE (2 2 ) contains a mixture of 50 vol. % feed gas stream A and 50 vol. % feed gas stream B. % Feedstream B, and pure feedstream B is supplied to the MTEs (2 3 to 2 10 ).

[0174] The retentate gas from the retentate gas line of the MTE that separates the mixed gas, in Example 2.1 MTE (2 2), flows in equal proportions towards the retentate gas outlet (12) and (13), respectively. The permeate gas from the MTE that separates the mixed gas also flows in equal proportions towards the permeate gas outlet (15) and (16), respectively. The retentate gases from the MTEs that only separate feed gas stream A, in Example 2.1 MTE (2 1), flow completely to the retentate gas outlet (12), and the retentate gases from the MTEs that only separate feed gas stream B, in Example 2.1 MTEs (2 3 to 2 10), flow completely to the retentate gas outlet (13). The permeate streams of the respective MTEs behave analogously. The previously described division of the flows to the retentate gas outlet (12) or (13) or the permeate gas outlet (15) or (16) is controlled by corresponding valves in the retentate gas outlet (12) or (13) or the permeate gas outlet (15) or (16).

[0175] The compositions, temperatures, volume flows, and pressures of the two feed gas streams A and B are given in Tables 3a and 3b. Tables 4a to 4d summarize the results of Examples 2.1 to 2.8. It is clearly evident that such operation compromises the separation efficiency of the smaller feed gas stream. For example, according to Example 2.1, with a feed gas stream A that is very low compared to feed gas stream B, a potential separation goal, such as methane enrichment, is not achieved. The methane purity in the retentate gas discharge (12) reaches only 88.6 vol% instead of the 99.4% achieved in the ideal case, as shown in Table 2a. However, Example 2.1 does achieve a significant enrichment of helium in the permeate gas discharge (15) from 10% in feed gas stream A to 28.7%. In the ideal case from example series 1, however, 42.1% would be achievable.

[0176] With the more balanced volume flows between feed gas streams A and B in examples 2.3 to 2.7, good separation results are obtained in all gas lines despite the operation with low mixing of the feed gas streams (12, 13, 15, 16). Table 3a Feed current A measured in the feed line (7) Example Pressure Temp. Flow He CH 4 # [bar(a)] [°C] [Nm 3< / h] [vol%] [vol% ] 2.1 10,08 25 150 10 90 2.2 10,08 25 250 10 90 2.3 10,09 25 350 10 90 2.4 10,09 25 450 10 90 2.5 10,09 25 550 10 90 2.6 10,09 25 650 10 90 2.7 10,1 25 750 10 90 2.8 10,1 25 850 10 90 Table 3b Feed current B measured in the feed line (8) Example Pressure Temp. Flow CO2 N 2 # [bar(a)] [°C] [Nm 3< / h] [vol% ] [vol% ] 2.1 10,1 25 850 40 60 2.2 10,1 25 750 40 60 2.3 10,1 25 650 40 60 2.4 10,09 25 550 40 60 2.5 10,09 25 450 40 60 2.6 10,09 25 350 40 60 2.7 10,09 25 250 40 60 2.8 10,08 25 150 40 60 Table 4a: First retentate stream in retentate gas vent (12) Example Pressure Temp. Flow He CH 4 CO2 N 2 CH4 yield # [bar(a)] [°C] [Nm 3< / h] [vol% ] [vol% ] [vol% ] [vol% ] [%] 2.1 10 24,0 108 0,48 88,6 0,24 10,66 71,1 2.2 10 24,3 186 0,55 93,1 0,14 6,21 76,9 2.3 10 24,5 264 0,57 94,9 0,10 4,38 79,4 2.4 10 24,5 341 0,59 96,0 0,08 3,38 80,8 2.5 10 24,6 419 0,60 96,6 0,06 2,76 81,7 2.6 10 24,6 497 0,60 97,0 0,05 2,33 82,3 2.7 10 24,6 574 0,61 97,3 0,05 2,01 82,8 2.8 10 24,7 652 0,61 97,6 0,04 1,77 83,1 Table 4b: Second retentate stream in retentate gas vent (13) Example Pressure Temp. Flow He CH 4 CO2 N 2 N2 yield # [bar(a)] [°C] [Nm 3< / h] [vol%] [vol%] [vol%] [vol%] [%] 2.1 10 22,0 377 0,01 4,99 0,44 94,6 69,8 2.2 10 22,1 333 0,01 5,64 0,44 93,9 69,6 2.3 10 22,1 290 0,01 6,48 0,45 93,1 69,2 2.4 10 22,2 247 0,01 7,61 0,46 91,9 68,8 2.5 10 22,3 204 0,01 9,23 0,47 90,3 68,1 2.6 10 22,4 160 0,01 11,72 0,49 87,8 67,0 2.7 10 22,6 117 0,02 16,04 0,52 83,4 65,1 2.8 10 23,0 74 0,03 25,44 0,59 73,9 60,7 Table 4c: First permeate stream in permeate gas discharge (15) Example Pressure Temp. Flow He CH 4 CO2 N 2 He yield # [bar(a)] [°C] [Nm 3< / h] [vol%] [vol%] [vol%] [vol%] [%] 2.1 1,01 23,6 42 28,7 39,7 23,3 8,28 79,9 2.2 1,01 24,3 64 33,5 45,9 15,2 5,39 85,9 2.3 1,01 24,6 86 35,9 48,9 11,3 4,00 88,5 2.4 1,01 24,8 109 37,2 50,6 8,95 3,18 90,0 2.5 1,01 25,0 131 38,1 51,8 7,43 2,63 90,9 2.6 1,01 25,1 153 38,8 52,6 6,35 2,25 91,5 2.7 1,01 25,1 176 39,2 53,3 5,54 1,96 92,0 2.8 1,01 25,2 198 39,6 53,7 4,92 1,74 92,4 Table 4d: Second permeate stream in permeate gas discharge (16) Example Pressure Temp. Flow He CH 4 CO2 N 2 CO2 yield # [bar(a)] [°C] [Nm 3< / h] [vol%] [vol%] [vol%] [vol%] [%] 2.1 1,01 21,5 473 0,52 0,78 69,4 29,3 96,6 2.2 1,01 21,5 417 0,59 0,89 69,2 29,3 96,2 2.3 1,01 21,5 360 0,69 1,03 69,1 29,2 95,6 2.4 1,01 21,6 303 0,82 1,22 68,9 29,1 94,9 2.5 1,01 21,6 246 1,01 1,51 68,6 28,9 93,9 2.6 1,01 21,7 190 1,31 1,96 68,1 28,6 92,3 2.7 1,01 21,9 133 1,86 2,79 67,3 28,1 89,4 2.8 1,01 22,4 76 3,25 4,88 65,1 26,8 82,6 Comparative example 1:

[0177] As a non-inventive example, a system is considered in which the two feed gas streams A and B of examples 1 and 2 are fed separately to a separate membrane separation stage 1 and 2, respectively.

[0178] Since the volumetric flow rates of the respective feed gas streams can fluctuate, as in Example Series 1 and 2, the number of MTEs connected in parallel in each of the membrane separation stages 1 and 2 must be designed for the maximum volumetric flow rate. This means that, compared to the 10 MTEs in Examples 1 and 2 according to the invention, twice as many MTEs (10 MTEs each) are now required. However, since the volumetric flow rates of the two feed gas streams vary, not all MTEs of the respective membrane separation stage 1 or 2 are fully utilized at every operating time. The result of the separation under these conditions, i.e., operation of the MTEs at partial load, is shown in Tables 6a to 6d. The compositions, temperatures, volumetric flow rates, and pressures of the two feed gas streams A and B can be found in Tables 5a and 5b. Table 5a: comparative example Feed Membrane Separation Stage 1 Pressure Temp. Flow He CH 4 # [bar(a)] [°C] [Nm 3< / h] [vol%] [vol%] 1.1 10,08 25 1000 10 90 1.2 10,08 25 950 10 90 1.3 10,09 25 850 10 90 1.4 10,09 25 750 10 90 1.5 10,09 25 650 10 90 1.6 10,09 25 550 10 90 1.7 10,1 25 450 10 90 1.8 10,1 25 350 10 90 1.9 10,1 25 250 10 90 Table 5b: comparative example Feed Membrane Separation Stage 2 Pressure Temp. Flow CO2 N 2 # [bar(a)] [°C] [Nm 3< / h] [vol%] [vol% ] 1.1 10,1 25 1000 40 60 1.2 10,1 25 950 40 60 1.3 10,1 25 850 40 60 1.4 10,09 25 750 40 60 1.5 10,09 25 650 40 60 1.6 10,09 25 550 40 60 1.7 10,09 25 450 40 60 1.8 10,08 25 350 40 60 1.9 10,08 25 250 40 60 Table 6a: comparative example Retentate of membrane separation stage 1 Pressure Temp. Flow He CH 4 CH4 yield # [bar(a)] [°C] [Nm 3< / h] [vol%] [vol%] [%] 1.1 10 24,8 777 0,64 99,4 85,7 1.2 10 24,8 730 0,53 99,5 85,0 1.3 10 24,7 639 0,32 99,7 83,2 1.4 10 24,5 548 0,16 99,8 81,0 1.5 10 24,4 457 0,06 99,9 78,1 1.6 10 24,1 367 0,01 100,0 74,2 1.7 10 23,7 278 0,00 100,0 68,6 1.8 10 22,9 189 0,00 100,0 60,1 1.9 10 21,1 102 0,00 100,0 45,4 Table 6b: comparative example Retentate of membrane separation stage 2 Pressure Temp. Flow CO2 N 2 N2 yield # [bar(a)] [°C] [Nm 3< / h] [vol% ] [vol%] [%] 1.1 10 21,8 432 0,40 99,6 71,8 1.2 10 21,5 402 0,28 99,7 70,3 1.3 10 21,4 340 0,11 99,9 66,7 1.4 10 21,3 279 0,03 100,0 62,1 1.5 10 21,1 219 0,00 100,0 56,1 1.6 10 20,6 158 0,00 100,0 48,0 1.7 10 19,8 99 0,00 100,0 36,7 1.8 10 17 44 0,00 100,0 20,7 1.9 10 2,7 7 0,00 100,0 4,7 Table 6c: comparative example Permeate membrane separation stage 1 Pressure Temp. Flow He CH 4 He yield # [bar(a)] [°C] [Nm 3< / h] [vol%] [vol%] [%] 1.1 1,01 26 223 42,5 57,5 95,0 1.2 1,01 26 220 41,5 58,5 96,0 1.3 1,01 26 211 39,2 60,8 97,6 1.4 1,01 26 202 36,6 63,4 98,8 1.5 1,01 26 193 33,6 66,4 99,6 1.6 1,01 26 183 30,1 69,9 99,9 1.7 1,01 26 172 26,2 73,8 100,0 1.8 1,01 25 161 21,8 78,2 100,0 1.9 1,01 25 148 16,9 83,1 100,0 Table 6d: comparative example Permeate membrane separation stage 2 Pressure Temp. Flow CO2 N 2 CO2 yield # [bar(a)] [°C] [Nm 3< / h] [vol% ] [vol%] [%] 1.1 1,01 21 568 70,2 29,8 99,6 1.2 1,01 22 548 69,1 30,9 99,7 1.3 1,01 22 509 66,7 33,3 99,9 1.4 1,01 22 471 63,7 36,3 100,0 1.5 1,01 22 431 60,3 39,7 100,0 1.6 1,01 22 392 56,2 43,8 100,0 1.7 1,01 22 351 51,3 48,7 100,0 1.8 1,01 22 307 45,7 54,3 100,0 1.9 1,01 21 243 41,2 58,8 100,0

[0179] The results in Tables 6a to 6d show that, despite using twice the number of MTEs compared to Examples 1 and 2 according to the invention, no satisfactory separation result can be achieved when operating the MTEs in the partial load range - due to variations in the feed streams.

[0180] In the apparatus used in the comparison example, one could, for example, install additional valves to shut off individual MTEs to ensure that the MTEs not shut off are always operated at full load. However, this would significantly increase the equipment complexity caused by doubling the number of MTEs and would require additional control engineering effort. Comparison of the separation efficiencies of examples 1 and 2 with comparison example 1

[0181] In the Figure 12The results of Examples 1, 2, and the comparative example are plotted for comparison. The plot shows the product of methane yield and purity in the retentate (retentate gas line (12)) relative to the maximum achievable value as a function of the feed gas quantity in Nm³ / h. Example 1 according to the invention always yields the maximum achievable product of CH₄ purity and CH₄ yield, and thus a relative value of 100%. In comparative example 1, the maximum value is only reached at full load of 1000 Nm³ / h and then drops rapidly. Example 2 according to the invention maintains relatively high values ​​over a wide partial load range.

[0182] Increasing the number of MTEs in Example Series 2, e.g., by using MTEs with lower separation capacity while maintaining the same total installed separation capacity, can significantly reduce the negative impact of partial mixing of the feed gas streams due to the dilution effect in the apparatus according to the invention. In limit value analysis, the ideal result of Example 1 is obtained with an infinitely high number of MTEs.

[0183] The use of several hundred membrane separation units is quite realistic in the field of gas separation. Example 3

[0184] Example 3 describes the operation according to the invention of a membrane separation stage with a membrane block (19) with 10 parallel-connected membrane separation units (2) according to Figure 1The system is considered in the area of ​​helium source gas. The individual membrane separation units (2) have the properties described in Example 1. The feed gas streams, which are supplied separately in the feed gas lines (7) and (8), are also ideally distributed as in Example 1. In contrast to Example 1, only one retentate gas stream (12) and one permeate gas stream (15) are generated, in which the retentate and permeate streams of the membrane separation units (2) are supplied via retentate and permeate gas lines (9) and (10) to a retentate and permeate gas collection pipe (11) and (14), respectively, each of which is connected to only one retentate and permeate gas outlet (12) and (15), respectively. Sampling points for determining the retentate concentration of the individual membrane separation units (2) were installed on the retentate gas lines (9).

[0185] Helium source gas refers to natural gas sources containing helium. Depending on the region, and sometimes even on the source within a smaller region, there are sometimes significantly different helium concentrations. In Example 3, it is assumed for simplicity that the two sources under consideration contain only helium and methane. Source 1 (feed gas stream 1) contains 1% helium, and Source 2 (feed gas stream 2) contains 3% helium. The goal of the separation is to obtain a helium content of only 0.2% in the retentate for both feed gas streams in order to achieve relatively good helium yields in the permeate. For the feed gas streams fed in as shown in Table 7, a helium concentration of 0.2% is obtained in each retentate gas line. Table 7 shows the fluxes and concentrations of the retentate and permeate gas streams. Table 7: Flow Pressure temperature He CH4 [Nm 3< / h] [bara] [°C] [vol%] [vol%] Feed gas flow 1 572 10,11 25,0 1,0 99,0 Feed gas flow 2 435 10,08 25,0 3,0 97,0 Retentate gas stream 861 10 24,6 0,20 99,80 Permeate gas stream 146 1,01 24,9 11,69 88,31 yield 90,8% 87% Comparative example 2

[0186] In the non-inventive comparative example 2 to example 3, the feed gas stream 1 from source 1 and feed gas stream 2 from source 2 are mixed and then supplied as a single feed gas stream via a feed gas line to the 10 membrane separation units, so that each membrane separation unit separates the same feed gas stream. The remaining setup of the membrane separation stage corresponds to example 3. The results are summarized in Table 8. Table 8: Flow Pressure temperature He CH4 [Nm 3< / h] [bara] [°C] [vol%] [vol%] Feed gas flow 1007 10,1 25,0 1,9 98,1 Retentate gas stream 861 10 24,5 0,24 99,76 Permeate gas stream 146 1,01 24,9 11,49 88,51 yield 89,0% 87,0%

[0187] Comparing Example 3 and Example 2, it becomes clear that the separate feeding of the feed gas streams, as described in Example 3, leads to an overall better separation result. Firstly, the purities achieved for helium in the permeate and methane in the retentate are higher in Example 3 than in Example 2. Furthermore, the helium yield in the permeate, i.e., the amount of helium in the permeate gas stream relative to the amount of helium in the feed gas stream, is higher in Example 3 than in Example 2. This means that more of the valuable helium is recovered at a higher purity. Comparing the situation for methane in the retentate gas stream, we find that even the product of methane purity and methane yield is slightly higher in Example 3 than in Example 2. Reference symbol list:

[0188] (1) Membrane block according to the invention (2) Membrane separation unit; the respective parallel-connected membrane separation units of a membrane block are indexed from (2 1 ) to (2 n ), wherein the index n corresponds to the consecutive number and the number n to the number of parallel-connected membrane separation units (3) Gas inlet of a membrane separation unit; the respective gas inlets of the parallel-connected membrane separation units of a membrane block are indexed from (3 1 ) to (3 n ), wherein the index n corresponds to the consecutive number and the number n to the number of parallel-connected membrane separation units (4) Distribution line; if several membrane blocks and thus several distribution lines are present in a membrane separation stage, these are indexed from (4 1 ) to (4 o ), wherein o corresponds to the consecutive number and the number o to the number of distribution lines contained in a membrane separation stage (5) Branch (6) Supply line to a gas inlet of a membrane separation unit; theThe respective feed lines of the parallel-connected membrane separation units of a membrane block are indexed from (6 1 ) to (6 n ), where the index n corresponds to the sequential number and the number n to the number of parallel-connected membrane separation units. (7) First feed gas line (8) Second feed gas line (9) Retentate gas line of a membrane separation unit; the respective retentate gas lines of the parallel-connected membrane separation units of a membrane block are indexed from (9 1 ) to (9 n ), where the index n corresponds to the sequential number and the number n to the number of parallel-connected membrane separation units. (10) Permeate gas line of a membrane separation unit; the respective permeate gas lines of the parallel-connected membrane separation units of a membrane block are indexed from (10 1 ) to (10 n ), where the index n corresponds to the sequential number and the number n to the number of parallel-connected membrane separation units. (11) Retentate gas collecting pipe (12)First retentate gas outlet (13) Second retentate gas outlet (14) Permeate gas collecting pipe (15) First permeate gas outlet (16) Second permeate gas outlet (18) Connecting lines (19a) Gas line (19b) Gas line (20a) Gas line (20b) Gas line (21) Third feed gas line (22) First permeate gas line of the second membrane separation stage B) (23) Second permeate gas line of the second membrane separation stage B) (24) First retentate gas line of the second membrane separation stage B) (25) Second retentate gas line of the second membrane separation stage B) (26) First permeate gas line of the third membrane separation stage C) (27) Second permeate gas line of the third membrane separation stage C) (28) First retentate gas line of the third membrane separation stage C) (29) Second retentate gas line of the third membrane separation stage C) (30) Retentate gas outlet of a membrane separation unit; The respective retentate gas outlets of the parallel-connected membrane separation units of a membrane block are indexed from (3 1 ) to (3 n ), where the index n is consecutive.(31) Permeate gas outlet of a membrane separation unit; the respective permeate gas outlets of the parallel-connected membrane separation units of a membrane block are indexed from (31) to (3n), where the index n is a consecutive number and the number n is the number of parallel-connected membrane separation units. (32) Retentate connecting line between two retentate gas outlets of two adjacent membrane separation units of a membrane block. (33) Permeate connecting line between two permeate gas outlets of two adjacent membrane separation units of a membrane block.

Claims

1. Plant for separation of gas mixtures, comprising a. a first feed gas conduit (7) suitable or configured for transportation of a first feed gas stream, and a second feed gas conduit (8) suitable or configured for transportation of a second feed gas stream of different composition from the first feed gas stream, b. a membrane separation stage, comprising one membrane block (1) or multiple membrane blocks (1), where the membrane block(s) (1) each comprise(s) multiple membrane separation units (2) connected in parallel, and where ∘ each membrane separation unit (2) has a gas inlet (3) and gas separation membranes, and the gas mixture supplied via the gas inlet (3) is separated by means of the gas separation membranes into a retentate gas stream and a permeate gas stream, and ∘ each membrane separation unit (2) has a retentate gas outlet (30) for the retentate gas stream which is preferably attached to a retentate gas conduit (9) or connected by means of one or more retentate connection conduit(s) (32) to one or two retentate gas outlet(s) (30) of the adjacent membrane separation unit(s) (2) of the same membrane block (1), and a permeate gas outlet (31) for the permeate gas stream which is preferably attached to a permeate gas conduit (10) or connected by means of one or more permeate connection conduit(s) (33) to one or two permeate gas outlet(s) (31) of the adjacent membrane separation unit(s) (2) of the same membrane block (1), and c. a gas distributor configured such that • it comprises connection conduits (18) that each connect the gas inlets (3) of two adjacent membrane separation units (2) of a membrane block (1) to one another and / or comprises one or more distributor conduit(s) (4) each containing multiple branches (5) that are each connected by means of supply conduits (6) to the gas inlets (3) of the individual membrane separation units (2) of a membrane block (1), where one or more branch(es) (5) may additionally also have an attachment means for a feed gas conduit, such that, by means of the branch(es) (5), a feed gas conduit and a supply conduit (6) may each be attached simultaneously to the respective distributor conduit (4), • if the membrane separation stage comprises multiple membrane blocks (1), it comprises pipe conduits, preferably pipe conduits (19a, 19b, 20a, 20b), that connect the membrane blocks (1) of the membrane separation stage to one another, • the first feed gas conduit (7) and the second feed gas conduit (8) are each independently attached at spatially separate sites to a distributor conduit (4) or a connection conduit (18) or a branch (5) or, if present, to a pipe conduit that connects the membrane blocks (1) of the membrane separation stage to one another, preferably a pipe conduit (19a, 19b, 20a or 20b), or to a gas inlet (3), where the attachment sites are arranged such that two or more than two branches (5) and / or two or more than two gas inlets (3) are arranged between the attachment sites of the first feed gas conduit (7) and of the second feed gas conduit (8).

2. Plant according to Claim 1, characterized in that the attachment sites of the first feed gas conduit (7) and the second feed gas conduit (8) are arranged such that the first feed gas stream and the second feed gas stream flow towards each other within one membrane block (1) or multiple membrane blocks (1) of the membrane separation stage, preferably in one or more distributor conduit(s) (4) and / or in one or more connection conduit(s) (18) or within the pipe conduit(s) that connect(s) the membrane blocks (1) of the membrane separation stage to one another, preferably the pipe conduit(s) (19a, 19b, 20a, 20b) .

3. Plant according to Claim 1 or 2, characterized in that the membrane separation stage contains one membrane block (1) or multiple membrane blocks (1) each comprising a distributor conduit (4) with multiple branches (5) and supply conduits (6), where one supply conduit (6) in each case connects a branch (5) to a gas inlet (3) of a membrane separation unit (2), and the first feed gas conduit (7) and the second feed gas conduit (8) are connected separately and independently to the distributor conduit(s) (4) and / or branches (5), more preferably to the respective opposite ends of the distributor conduit(s) (4).

4. Plant according to Claim 1 or 2, characterized in that the membrane separation stage contains one membrane block (1) or multiple membrane blocks (1) each comprising multiple connection conduits (18) that each connect a gas inlet (3) of a membrane separation unit (2) to the gas inlet(s) (3) of the adjacent membrane separation unit(s) (2) in the membrane block (1), and the first feed gas conduit (7) and the second feed gas conduit (8) are each separately and independently connected to one gas inlet (3) of a membrane separation unit (2) or multiple gas inlets (3) of membrane separation units (2) and / or to one connection conduit (18) or multiple connection conduits (18).

5. Plant according to any of Claims 1 to 4, characterized in that it additionally comprises one, two or three feed gas conduit(s) three (21), four and five, which is / are suitable for transportation of one, two or three additional gas streams of different composition from the first and second feed gas streams, and the additional feed gas conduit(s) three (21), four and five is / are connected to the gas distributor such that gas stream three (21) or gas streams three (21) and four or gas streams three (21), four and five can be supplied to the membrane separation units by means of the gas distributor.

6. Plant according to Claim 5, characterized in that the feed gas conduit(s) three (21) or three (21) and four or three (21), four and five is / are each independently • attached to one or more distributor conduit(s) (4), preferably between the attachments of the first feed gas conduit (7) and the second feed gas conduit (8), and / or • attached to one or more connection conduit(s) (18), preferably between the attachments of the first feed gas conduit (7) and the second feed gas conduit (8), and / or • attached to one gas inlet (3) or multiple gas inlets (3), where the gas inlet (3) or these gas inlets (3) are more preferably different from the gas inlets (3) to which the first feed gas conduit (7) or the second feed gas conduit (8) are attached, and / or • attached to one gas inlet (3) or multiple gas inlets (3) and one connection conduit (18) or multiple connection conduits (18), where these gas inlets (3) are preferably different from the gas inlets (3) to which the first feed gas conduit (7) or the second feed gas conduit (8) is attached.

7. Plant according to Claim 5, characterized in that the membrane separation stage comprises multiple membrane blocks (1) that are combined to form a ring circuit, where each membrane block (1) is preferably connected to two feed gas conduits.

8. Plant according to any of Claims 1 to 6, characterized in that the membrane separation stage comprises multiple membrane blocks (1) connected in parallel.

9. Plant according to Claim 8, characterized in that the gas distributor comprises one distributor conduit (4) with multiple branches (5) and supply conduits (6) per membrane block (1), where one supply conduit (6) in each case connects a branch (5) to a gas inlet (3) of a membrane separation unit (2), and the distributor conduits (4) of the respective membrane blocks (1) of the membrane separation stage are connected to one another by means of pipe conduits (19a, 19b), and the first feed gas conduit (7) and the second feed gas conduit (8) are independently attached at spatially separate sites to a distributor conduit (4) or a branch (5), or to a pipe conduit (19a, 19b), where the attachment sites are arranged such that two or more than two branches (5) and / or two or more than two gas inlets (3) are disposed between the attachment sites of the first feed gas conduit (7) and of the second feed gas conduit (8).

10. Plant according to Claim 8, characterized in that the gas distributor in the respective membrane block (1) comprises connection conduits (18) that each connect the gas inlet (3) of a membrane separation unit (2) to the gas inlet (s) (3) of the adjacent membrane separation unit(s) (2) in the membrane block (1), and the membrane blocks (1) of the membrane separation stage are connected to one another by means of pipe conduits (20a, 20b), where the pipe conduits (20a, 20b) in the respective membrane block (1) are each connected to one or more connection conduit(s) (18) and / or one or more gas inlet(s) (3), preferably where the pipe conduit (20a) in the respective membrane block (1) is connected to a connection conduit (18) or a gas inlet (3) and the pipe conduit (20b) in the respective membrane block is connected to a different connection conduit (18) or a different gas inlet (3), and the first feed gas conduit (7) and the second feed gas conduit (8) are independently attached at spatially separate sites to one or more connection conduit(s) (18), or to one or more pipe conduit(s) (20a, 20b), or to one or more gas inlet(s) (3), where the attachment sites are arranged such that two or more than two gas inlets (3) are arranged between the attachment sites of the first feed gas conduit (7) and the second feed gas conduit (8).

11. Plant according to any of Claims 1 to 10, characterized in that, in one or more distributor conduit(s) (4) and / or one or more connection conduit(s) (18) and / or one or more pipe conduit(s) (19a, 19b, 20a, 20b), at potential contact sites of the feed gas streams that meet in the conduit, construction measures is / are taken for control and / or substantial prevention of full mixing of the feed gas streams, preferably selected from the list consisting of reduction of the conduit cross sections, extension of the conduit sections, introduction of static mixers, insertion of pigs in the gas conduits, and combinations thereof.

12. Plant according to any of Claims 1 to 11, characterized in that the retentate gas conduits (9), preferably all retentate gas conduits (9), of the membrane separation units (2) of a membrane block (1) of the membrane separation stage are supplied to a retentate gas collection pipe (11), where the retentate gas collection pipe (11) is connected to at least one first retentate gas vent (12), preferably at least two retentate gas vents (12) and (13), and / or the permeate gas conduits (10), preferably all permeate gas conduits (10), of the membrane separation units (2) of a membrane block (1) of the membrane separation stage are supplied to a permeate gas collection pipe (14), where the permeate gas collection pipe is connected to at least one first permeate gas outlet (15), preferably at least two permeate gas outlets (15) and (16).

13. Plant according to any of Claims 1 to 11, characterized in that it comprises retentate connection conduits (32) between the retentate gas outlets (30) of the membrane separation units (2) of a membrane block (1) of the membrane separation stage, where at least one retentate connection conduit (32) or at least one retentate gas outlet (30) is additionally connected to at least one retentate gas vent (12), preferably where one or more retentate connection conduit(s) (32) and / or one or more retentate gas outlet(s) (30) in one membrane block (1) of the membrane separation stage are each independently connected to one retentate gas vent (12) or (13), and / or it comprises permeate connection conduits (33) between the permeate gas outlets (31) of the membrane separation units (2) of a membrane block (1) of the membrane separation stage, where at least one permeate connection conduit (33) or at least one permeate gas outlet (31) is additionally connected to at least one permeate gas vent (15), preferably where one or more permeate connection conduit(s) (33) and / or one or more permeate gas outlet(s) (31) in one membrane block (1) of the membrane separation stage are each independently connected to one retentate gas vent (15) or (16).

14. Plant according to any of Claims 1 to 13, characterized in that it comprises two membrane separation stages A and B according to Claim 1, where a first feed gas conduit (7) and a second feed gas conduit (8) are connected to the gas distributor of the first membrane separation stage A as described in any of Claims 1 to 10, and the first membrane separation stage A is configured such that two different retentate streams are obtained in a first retentate gas vent (12) and a second retentate gas vent (13) and / or two different permeate streams are obtained in a first permeate gas vent (15) and a second permeate gas vent (16), and the first retentate gas vent (12) and the second retentate gas vent (13) or the first permeate gas vent (15) and the second permeate gas vent (16) are connected to the gas distributor of the second membrane separation stage B as described in any of Claims 1 to 10.

15. Plant according to any of Claims 1 to 13, characterized in that it comprises three membrane separation stages A, B and C according to Claim 1, where a first feed gas conduit (7) and a second feed gas conduit (8) are connected to the gas distributor of the first membrane separation stage A as described in any of Claims 1 to 10, and the first membrane separation stage A is configured such that two different retentate streams are obtained in a first retentate gas vent (12) and a second retentate gas vent (13) and two different permeate streams are obtained in a first permeate gas vent (15) and a second permeate gas vent (16), and the first retentate gas vent (12) and the second retentate gas vent (13) are connected to the gas distributor of the second membrane separation stage B as described in any of Claims 1 to 10, and the first permeate gas vent (15) and the second permeate gas vent (16) are connected to the gas distributor of the third membrane separation stage C as described in any of Claims 1 to 10.

16. Process for simultaneously purifying two or more gas streams of respectively different composition, characterized in that the separation of the gases is conducted in a plant according to any of Claims 1 to 15.

17. Process according to Claim 16, characterized in that it comprises the steps of i) providing a first feed gas stream, ii) providing a second feed gas stream of different composition from the first feed gas stream, iii) feeding the first and second feed gas streams to a membrane separation stage, where • the membrane separation stage has one membrane separation block (1) or multiple membrane blocks (1), and the membrane separation block(s) (1) each comprise(s) multiple membrane separation units (2) connected in parallel, and where • the membrane separation stage has a gas distributor comprising connection conduits (18) that each connect the gas inlets (3) of two adjacent membrane separation units (2) of a membrane block (1) to one another and / or distributor conduits (4) containing multiple branches (5) that are each connected by means of separate supply conduits (6) to the gas inlets (3) of the individual membrane separation units (2) of a membrane block (1), where one or more branch(es) (5) may additionally also have an attachment means for a feed gas conduit, such that, by means of the branch(es) (5), a feed gas conduit and a supply conduit (6) may be attached simultaneously to the distributor conduit (4), and where • the membrane separation stage, if it comprises multiple membrane blocks (1), comprises pipe conduits, preferably pipe conduits (19a, 19b, 20a, 20b), that connect the membrane blocks (1) of the membrane separation stage to one another, and where the first and second feed gas streams are each independently supplied at spatially separate sites to a distributor conduit (4) or a connection conduit (18) or a branch (5) or, if present, to a pipe conduit that connects the membrane blocks (1) of the membrane separation stage to one another, preferably a pipe conduit (19a, 19b, 20a, 20b), or to a gas inlet (3), where the attachment sites of the first and second feed gas streams are arranged such that two or more than two branches (5) and / or two or more than two gas inlets (3) are arranged between the attachment sites, iv) supplying the first and second feed gas streams by means of the gas distributor to the gas inlets (3) of the membrane separation units (2) of the membrane separation stage, v) separating the gas mixtures supplied via the gas inlets (3) to the membrane separation units (2) by means of gas separation membranes in the membrane separation units (2), in each case into a retentate gas stream and a permeate gas stream.

18. Process according to Claim 17, characterized in that the first and second feed gas streams are supplied by means of a gas distributor to the gas inlets (3) of the membrane separation units (2) of the first membrane separation stage such that the first feed gas stream and the second feed gas stream flow towards each other within one membrane block (1) or multiple membrane blocks (1) of the membrane separation stage, preferably in one or more distributor conduit(s) (4) and / or one or more connection conduit(s) (18) and / or within the pipe conduit(s) that connect(s) the membrane blocks (1) of the membrane separation stage to one another, preferably the pipe conduit(s) (19a, 19b, 20a, 20b), and / or at least two different membrane separation units (2) in one membrane block (1), preferably in multiple membrane blocks (1), more preferably in all membrane blocks (1), of the membrane separation stage are each supplied with gas streams of different composition.

19. Process according to Claim 17 or 18, characterized in that the membrane separation stage contains one membrane block (1) or multiple membrane blocks (1) each comprising a distributor conduit (4) with multiple branches (5) and supply conduits (6), where each supply conduit (6) connects a branch (5) to a gas inlet (3) of a membrane separation unit (2), and the first feed gas stream and the second feed gas stream are supplied separately and independently to the distributor conduit(s) (4), more preferably to the respective opposite ends of the distributor conduit(s) (4).

20. Process according to either of Claims 17 and 18, characterized in that the membrane separation stage contains one membrane block (1) or multiple membrane blocks (1) each comprising multiple connection conduits (18) that each connect the gas inlet (3) of a membrane separation unit (2) to the gas inlet (s) (3) of the adjacent membrane separation unit(s) (2) in the membrane block (1), and the first feed gas stream and the second feed gas stream are each separately and independently supplied to one gas inlet of a membrane separation unit (2) or multiple gas inlets (3) of membrane separation units (2) and / or to one connection conduit (18) or multiple connection conduits (18).

21. Process according to any of Claims 17 to 20, characterized in that one, two or three additional gas stream(s) of different composition from the first and second feed gas streams is / are supplied to the gas distributor by means of the feed gas conduit(s) three (21), three (21) and four, or three (21), four and five.

22. Process according to Claim 21, characterized in that feed gas stream three (21) or feed gas streams three (21) and four or feed gas streams three (21), four and five is / are each • supplied to one or more distributor conduit(s) (4), preferably between the attachments of the first feed gas conduit (7) and the second feed gas conduit (8), and / or • supplied to one or more connection conduit(s) (18), preferably between the attachments of the first feed gas conduit (7) and the second feed gas conduit (8), and / or • supplied to one gas inlet (3) or multiple gas inlets (3), preferably in a membrane block (1) comprising connection conduits (18), where these gas inlets (3) are more preferably different from the gas inlets (3) to which the first feed gas stream or the second feed gas stream are supplied, and / or • supplied to one gas inlet (3) or multiple gas inlets (3) and to one or more connection conduit(s) (18), where these gas inlets (3) are preferably different from the gas inlets (3) and connection conduit(s) (18) to which the first feed gas stream or the second feed gas stream are supplied.

23. Process according to Claim 22, characterized in that multiple membrane blocks (1) of the membrane separation stage are combined to form a ring circuit, where each membrane block (1) is preferably supplied with two feed gas streams.

24. Process according to any of Claims 17 to 22, characterized in that multiple membrane blocks (1) of the membrane separation stage are connected in parallel.

25. Process according to Claim 24, characterized in that the gas distributor comprises one distributor conduit (4) with multiple branches (5) and supply conduits (6) per membrane block (1), where one supply conduit (6) in each case connects a branch (5) to a gas inlet (3) of a membrane separation unit (2), and the distributor conduits (4) of the respective membrane blocks (1) of the membrane separation stage are connected to one another by means of pipe conduits (19a, 19b), and the first feed gas stream and the second feed gas stream are supplied separately and independently to one or more distributor conduit(s) (4) and / or pipe conduit(s) (19a, 19b).

26. Process according to Claim 24, characterized in that the gas distributor in the respective membrane block (1) comprises connection conduits (18) that each connect the gas inlet (3) of a membrane separation unit (2) to the gas inlet (s) (3) of the adjacent membrane separation unit(s) (2) in the membrane block (1), and the membrane blocks (1) of the membrane separation stage are connected to one another by means of pipe conduits (20a, 20b), where the pipe conduits (20a, 20b) in the respective membrane block are each connected to one or more connection conduit(s) (18) or gas inlet(s) (3), preferably where the pipe conduit (20a) in the respective membrane block is connected to a connection conduit (18) or a gas inlet (3) and the pipe conduit (20b) in the respective membrane block is connected to a different connection conduit (18) or a different gas inlet (3), and the first feed gas stream and the second feed gas stream are supplied separately and independently to one gas inlet (3) or multiple gas inlets (3) of membrane separation units (2) and / or to one or more connection conduit(s) (18) of the respective membrane blocks (1) of the membrane separation stage and / or pipe conduit(s) (20a, 20b), with the proviso that the first feed gas stream and the second feed gas stream are not supplied simultaneously to the same gas inlets (3) or connection conduits (18) or supplied simultaneously to one or more identical and simultaneously to multiple nonidentical gas inlets (3) or connection conduits (18).

27. Process according to any of Claims 17 to 26, characterized in that, in one or more distributor conduit(s) (4) and / or one or more connection conduit(s) (18) and / or one or more pipe conduit(s) (19a, 19b, 20a, 20b), at potential contact sites of the feed gas streams that meet in the conduit, construction measures are taken for control and / or substantial prevention of full mixing of the feed gas streams, preferably selected from the list consisting of reduction of the conduit cross sections, extension of the conduit sections, introduction of static mixers, insertion of pigs in the gas conduits, and combinations thereof.

28. Process according to any of Claims 17 to 27, characterized in that it additionally comprises the steps of vi) combining retentate gas streams from the membrane separation units (2) of a membrane block (1) to give one or more retentate gas stream(s), and / or vii) combining permeate streams from the membrane separation units (2) of a membrane block (1) to give one or more permeate gas stream(s).

29. Process according to Claim 28, characterized in that the retentate streams from the membrane separation units (2) of a membrane block (1) of the membrane separation stage are supplied to a retentate gas collection pipe (11), where they are either combined to form one retentate gas stream and supplied to a retentate gas vent (12), or where they are divided into at least two retentate gas streams 1 and 2 and supplied to at least two retentate gas vents (12) and (13), and / or the permeate streams from the membrane separation units (2) of a membrane block (1) of the membrane separation stage are supplied to a permeate gas collection pipe (14), where they are either combined to form one permeate gas stream and supplied to a permeate gas vent (15), or where they are divided into at least two permeate gas streams 1 and 2 and supplied to at least two permeate gas vents (15) and (16).

30. Process according to Claim 28, characterized in that the retentate gas streams from the membrane separation units (2) of a membrane block (1) of the membrane separation stage are combined by means of retentate connection conduits (32) between the retentate gas outlets (30) of the membrane separation units (2) of a membrane block (1) of the membrane separation stage to form one retentate gas stream and supplied to a retentate gas vent (12), or they are divided into at least two retentate gas streams 1 and 2 and supplied to at least two retentate gas vents (12) and (13), and / or the permeate gas streams from the membrane separation units (2) of a membrane block (1) of the membrane separation stage are combined by means of permeate connection conduits (33) between the permeate gas outlets (31) of the membrane separation units (2) of a membrane block (1) of the membrane separation stage to form one permeate gas stream and supplied to a permeate gas vent (15), or they are divided into at least two permeate gas streams 1 and 2 and supplied to at least two permeate gas vents (15) and (16).

31. Process according to any of Claims 17 to 30, characterized in that it is executed in a plant comprising two membrane separation stages A and B according to Claim 14, where the first feed gas stream and the second feed gas stream of different composition are supplied to membrane separation stage A as described in any of Claims 17 to 27, the first membrane separation stage A separates the first feed gas stream and the second feed gas stream into a first retentate gas stream and a second retentate gas stream of different composition, and / or a first permeate gas stream and a second permeate gas stream of different composition, the two retentate streams or the two permeate streams from the first membrane separation stage A are supplied to the second membrane separation stage B as two feed streams of different composition, and the second membrane separation stage B separates the two retentate or permeate streams from membrane separation stage A into a third retentate gas stream and a fourth retentate gas stream of different composition, and / or into a third permeate gas stream and a fourth permeate gas stream of different composition.

32. Process according to any of Claims 17 to 30, characterized in that it is executed in a plant comprising three membrane separation stages A, B and C according to Claim 15, where the first feed gas stream and the second feed gas stream of different composition are supplied to membrane separation stage A as described in any of Claims 17 to 27, the first membrane separation stage A separates the first feed gas stream and the second feed gas stream into a first retentate gas stream and a second retentate gas stream of different composition, and into a first permeate gas stream and a second permeate gas stream of different composition, the two retentate streams from the first membrane separation stage A are supplied to the second membrane separation stage B as two feed streams of different composition, the second membrane separation stage B separates the two retentate gas streams from membrane separation stage A into a third retentate gas stream and a fourth retentate gas stream of different composition, the two permeate gas streams from the first membrane separation stage A are supplied to the third membrane separation stage C as two feed streams of different composition, the third membrane separation stage C separates the two permeate gas streams from membrane separation stage A into a fifth permeate gas stream and a sixth permeate gas stream of different composition.